Files @ de0b4c3c6dc2
Branch filter:

Location: therm/libraries/STM32L1xx_StdPeriph_Driver/src/stm32l1xx_usart.c

Ethan Zonca
Attempted USB fixes
   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
/**
  ******************************************************************************
  * @file    stm32l1xx_usart.c
  * @author  MCD Application Team
  * @version V1.2.0
  * @date    22-February-2013
  * @brief   This file provides firmware functions to manage the following 
  *          functionalities of the Universal synchronous asynchronous receiver
  *          transmitter (USART):           
  *           + Initialization and Configuration
  *           + Data transfers
  *           + Multi-Processor Communication
  *           + LIN mode
  *           + Half-duplex mode
  *           + Smartcard mode
  *           + IrDA mode
  *           + DMA transfers management
  *           + Interrupts and flags management 
  *           
  *  @verbatim
 ===============================================================================
                       ##### How to use this driver #####
 ===============================================================================
    [..]
        (#) Enable peripheral clock using
            RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE) function for
            USART1 or using RCC_APB1PeriphClockCmd(RCC_APB1Periph_USARTx, ENABLE)
            function for USART2 and USART3.
        (#) According to the USART mode, enable the GPIO clocks using
            RCC_AHBPeriphClockCmd() function. (The I/O can be TX, RX, CTS,
            or and SCLK).
        (#) Peripheral's alternate function:
            (++) Connect the pin to the desired peripherals' Alternate
                 Function (AF) using GPIO_PinAFConfig() function.
            (++) Configure the desired pin in alternate function by:
                 GPIO_InitStruct->GPIO_Mode = GPIO_Mode_AF.
            (++) Select the type, pull-up/pull-down and output speed via
                 GPIO_PuPd, GPIO_OType and GPIO_Speed members.
            (++) Call GPIO_Init() function.
        (#) Program the Baud Rate, Word Length , Stop Bit, Parity, Hardware
               flow control and Mode(Receiver/Transmitter) using the SPI_Init()
               function.
        (#) For synchronous mode, enable the clock and program the polarity,
            phase and last bit using the USART_ClockInit() function.
        (#) Enable the NVIC and the corresponding interrupt using the function
            USART_ITConfig() if you need to use interrupt mode.
        (#) When using the DMA mode.
            (++) Configure the DMA using DMA_Init() function.
            (++) Active the needed channel Request using USART_DMACmd() function.
        (#) Enable the USART using the USART_Cmd() function.
        (#) Enable the DMA using the DMA_Cmd() function, when using DMA mode.
    [..]
        Refer to Multi-Processor, LIN, half-duplex, Smartcard, IrDA sub-sections
        for more details.
  
@endverbatim
          
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2013 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "stm32l1xx_usart.h"
#include "stm32l1xx_rcc.h"

/** @addtogroup STM32L1xx_StdPeriph_Driver
  * @{
  */

/** @defgroup USART 
  * @brief USART driver modules
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/

/*!< USART CR1 register clear Mask ((~(uint16_t)0xE9F3)) */
#define CR1_CLEAR_MASK            ((uint16_t)(USART_CR1_M | USART_CR1_PCE | \
                                              USART_CR1_PS | USART_CR1_TE | \
                                              USART_CR1_RE))

/*!< USART CR2 register clock bits clear Mask ((~(uint16_t)0xF0FF)) */
#define CR2_CLOCK_CLEAR_MASK      ((uint16_t)(USART_CR2_CLKEN | USART_CR2_CPOL | \
                                              USART_CR2_CPHA | USART_CR2_LBCL))

/*!< USART CR3 register clear Mask ((~(uint16_t)0xFCFF)) */
#define CR3_CLEAR_MASK            ((uint16_t)(USART_CR3_RTSE | USART_CR3_CTSE))

/*!< USART Interrupts mask */
#define IT_MASK                   ((uint16_t)0x001F)

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/

/** @defgroup USART_Private_Functions
  * @{
  */

/** @defgroup USART_Group1 Initialization and Configuration functions
 *  @brief   Initialization and Configuration functions 
 *
@verbatim
 ===============================================================================
          ##### Initialization and Configuration functions #####
 ===============================================================================
    [..]
        This subsection provides a set of functions allowing to initialize the USART 
        in asynchronous and in synchronous modes.
        (+) For the asynchronous mode only these parameters can be configured: 
        (+) Baud Rate.
        (+) Word Length.
        (+) Stop Bit.
        (+) Parity: If the parity is enabled, then the MSB bit of the data written
          in the data register is transmitted but is changed by the parity bit.
          Depending on the frame length defined by the M bit (8-bits or 9-bits),
          the possible USART frame formats are as listed in the following table:
    [..]
   +-------------------------------------------------------------+
   |   M bit |  PCE bit  |            USART frame                |
   |---------------------|---------------------------------------|
   |    0    |    0      |    | SB | 8 bit data | STB |          |
   |---------|-----------|---------------------------------------|
   |    0    |    1      |    | SB | 7 bit data | PB | STB |     |
   |---------|-----------|---------------------------------------|
   |    1    |    0      |    | SB | 9 bit data | STB |          |
   |---------|-----------|---------------------------------------|
   |    1    |    1      |    | SB | 8 bit data | PB | STB |     |
   +-------------------------------------------------------------+
    [..]
        (+) Hardware flow control.
        (+) Receiver/transmitter modes.
    [..] The USART_Init() function follows the USART  asynchronous configuration 
         procedure(details for the procedure are available in reference manual 
         (RM0038)).
        (+) For the synchronous mode in addition to the asynchronous mode parameters
            these parameters should be also configured:
            (++) USART Clock Enabled.
            (++) USART polarity.
            (++) USART phase.
            (++) USART LastBit.
    [..] These parameters can be configured using the USART_ClockInit() function.

@endverbatim
  * @{
  */
  
/**
  * @brief  Deinitializes the USARTx peripheral registers to their default reset values.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values: USART1, USART2, USART3, 
  *   UART4 or UART5.
  * @retval None.
  */
void USART_DeInit(USART_TypeDef* USARTx)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));

  if (USARTx == USART1)
  {
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, ENABLE);
    RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, DISABLE);
  }
  else if (USARTx == USART2)
  {
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2, ENABLE);
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART2, DISABLE);
  }
  else if (USARTx == USART3)
  {
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART3, ENABLE);
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART3, DISABLE);
  }    
  else if (USARTx == UART4)
  {
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_UART4, ENABLE);
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_UART4, DISABLE);
  }    
  else
  {
    if (USARTx == UART5)
    { 
      RCC_APB1PeriphResetCmd(RCC_APB1Periph_UART5, ENABLE);
      RCC_APB1PeriphResetCmd(RCC_APB1Periph_UART5, DISABLE);
    }
  }   
}

/**
  * @brief  Initializes the USARTx peripheral according to the specified
  *   parameters in the USART_InitStruct.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values: USART1, USART2, USART3, 
  *   UART4 or UART5.
  * @param  USART_InitStruct: pointer to a USART_InitTypeDef structure that 
  *        contains the configuration information for the specified USART peripheral.
  * @retval None.
  */
void USART_Init(USART_TypeDef* USARTx, USART_InitTypeDef* USART_InitStruct)
{
  uint32_t tmpreg = 0x00, apbclock = 0x00;
  uint32_t integerdivider = 0x00;
  uint32_t fractionaldivider = 0x00;
  RCC_ClocksTypeDef RCC_ClocksStatus;

  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_BAUDRATE(USART_InitStruct->USART_BaudRate));  
  assert_param(IS_USART_WORD_LENGTH(USART_InitStruct->USART_WordLength));
  assert_param(IS_USART_STOPBITS(USART_InitStruct->USART_StopBits));
  assert_param(IS_USART_PARITY(USART_InitStruct->USART_Parity));
  assert_param(IS_USART_MODE(USART_InitStruct->USART_Mode));
  assert_param(IS_USART_HARDWARE_FLOW_CONTROL(USART_InitStruct->USART_HardwareFlowControl));

  /* The hardware flow control is available only for USART1, USART2 and USART3 */
  if (USART_InitStruct->USART_HardwareFlowControl != USART_HardwareFlowControl_None)
  {
    assert_param(IS_USART_123_PERIPH(USARTx));
  }
   
/*---------------------------- USART CR2 Configuration -----------------------*/
  tmpreg = USARTx->CR2;
  /* Clear STOP[13:12] bits */
  tmpreg &= (uint32_t)~((uint32_t)USART_CR2_STOP);

  /* Configure the USART Stop Bits, Clock, CPOL, CPHA and LastBit ------------*/
  /* Set STOP[13:12] bits according to USART_StopBits value */
  tmpreg |= (uint32_t)USART_InitStruct->USART_StopBits;
  
  /* Write to USART CR2 */
  USARTx->CR2 = (uint16_t)tmpreg;

/*---------------------------- USART CR1 Configuration -----------------------*/
  tmpreg = USARTx->CR1;
  /* Clear M, PCE, PS, TE and RE bits */
  tmpreg &= (uint32_t)~((uint32_t)CR1_CLEAR_MASK);

  /* Configure the USART Word Length, Parity and mode ----------------------- */
  /* Set the M bits according to USART_WordLength value */
  /* Set PCE and PS bits according to USART_Parity value */
  /* Set TE and RE bits according to USART_Mode value */
  tmpreg |= (uint32_t)USART_InitStruct->USART_WordLength | USART_InitStruct->USART_Parity |
            USART_InitStruct->USART_Mode;

  /* Write to USART CR1 */
  USARTx->CR1 = (uint16_t)tmpreg;

/*---------------------------- USART CR3 Configuration -----------------------*/  
  tmpreg = USARTx->CR3;
  /* Clear CTSE and RTSE bits */
  tmpreg &= (uint32_t)~((uint32_t)CR3_CLEAR_MASK);

  /* Configure the USART HFC -------------------------------------------------*/
  /* Set CTSE and RTSE bits according to USART_HardwareFlowControl value */
  tmpreg |= USART_InitStruct->USART_HardwareFlowControl;

  /* Write to USART CR3 */
  USARTx->CR3 = (uint16_t)tmpreg;

/*---------------------------- USART BRR Configuration -----------------------*/
  /* Configure the USART Baud Rate -------------------------------------------*/
  RCC_GetClocksFreq(&RCC_ClocksStatus);
  if (USARTx == USART1) 
  {
    apbclock = RCC_ClocksStatus.PCLK2_Frequency;
  }
  else
  {
    apbclock = RCC_ClocksStatus.PCLK1_Frequency;
  }

  /* Determine the integer part */
  if ((USARTx->CR1 & USART_CR1_OVER8) != 0)
  {
    /* Integer part computing in case Oversampling mode is 8 Samples */
    integerdivider = ((25 * apbclock) / (2 * (USART_InitStruct->USART_BaudRate)));    
  }
  else /* if ((USARTx->CR1 & CR1_OVER8_Set) == 0) */
  {
    /* Integer part computing in case Oversampling mode is 16 Samples */
    integerdivider = ((25 * apbclock) / (4 * (USART_InitStruct->USART_BaudRate)));    
  }
  tmpreg = (integerdivider / 100) << 4;

  /* Determine the fractional part */
  fractionaldivider = integerdivider - (100 * (tmpreg >> 4));

  /* Implement the fractional part in the register */
  if ((USARTx->CR1 & USART_CR1_OVER8) != 0)
  {
    tmpreg |= ((((fractionaldivider * 8) + 50) / 100)) & ((uint8_t)0x07);
  }
  else /* if ((USARTx->CR1 & CR1_OVER8_Set) == 0) */
  {
    tmpreg |= ((((fractionaldivider * 16) + 50) / 100)) & ((uint8_t)0x0F);
  }
 
  /* Write to USART BRR */
  USARTx->BRR = (uint16_t)tmpreg;
}

/**
  * @brief  Fills each USART_InitStruct member with its default value.
  * @param  USART_InitStruct: pointer to a USART_InitTypeDef structure
  *   which will be initialized.
  * @retval None
  */
void USART_StructInit(USART_InitTypeDef* USART_InitStruct)
{
  /* USART_InitStruct members default value */
  USART_InitStruct->USART_BaudRate = 9600;
  USART_InitStruct->USART_WordLength = USART_WordLength_8b;
  USART_InitStruct->USART_StopBits = USART_StopBits_1;
  USART_InitStruct->USART_Parity = USART_Parity_No ;
  USART_InitStruct->USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_InitStruct->USART_HardwareFlowControl = USART_HardwareFlowControl_None;  
}

/**
  * @brief  Initializes the USARTx peripheral Clock according to the 
  *         specified parameters in the USART_ClockInitStruct.
  * @param  USARTx: where x can be 1, 2, 3 to select the USART peripheral.
  * @param  USART_ClockInitStruct: pointer to a USART_ClockInitTypeDef
  *         structure that contains the configuration information for the specified 
  *         USART peripheral.
  * @note The Smart Card and Synchronous modes are not available for UART4 and UART5.
  * @retval None.
  */
void USART_ClockInit(USART_TypeDef* USARTx, USART_ClockInitTypeDef* USART_ClockInitStruct)
{
  uint32_t tmpreg = 0x00;
  /* Check the parameters */
  assert_param(IS_USART_123_PERIPH(USARTx));
  assert_param(IS_USART_CLOCK(USART_ClockInitStruct->USART_Clock));
  assert_param(IS_USART_CPOL(USART_ClockInitStruct->USART_CPOL));
  assert_param(IS_USART_CPHA(USART_ClockInitStruct->USART_CPHA));
  assert_param(IS_USART_LASTBIT(USART_ClockInitStruct->USART_LastBit));
  
/*---------------------------- USART CR2 Configuration -----------------------*/
  tmpreg = USARTx->CR2;
  /* Clear CLKEN, CPOL, CPHA and LBCL bits */
  tmpreg &= (uint32_t)~((uint32_t)CR2_CLOCK_CLEAR_MASK);
  /* Configure the USART Clock, CPOL, CPHA and LastBit ------------*/
  /* Set CLKEN bit according to USART_Clock value */
  /* Set CPOL bit according to USART_CPOL value */
  /* Set CPHA bit according to USART_CPHA value */
  /* Set LBCL bit according to USART_LastBit value */
  tmpreg |= (uint32_t)USART_ClockInitStruct->USART_Clock | USART_ClockInitStruct->USART_CPOL | 
                 USART_ClockInitStruct->USART_CPHA | USART_ClockInitStruct->USART_LastBit;
  /* Write to USART CR2 */
  USARTx->CR2 = (uint16_t)tmpreg;
}

/**
  * @brief  Fills each USART_ClockInitStruct member with its default value.
  * @param  USART_ClockInitStruct: pointer to a USART_ClockInitTypeDef
  *   structure which will be initialized.
  * @retval None
  */
void USART_ClockStructInit(USART_ClockInitTypeDef* USART_ClockInitStruct)
{
  /* USART_ClockInitStruct members default value */
  USART_ClockInitStruct->USART_Clock = USART_Clock_Disable;
  USART_ClockInitStruct->USART_CPOL = USART_CPOL_Low;
  USART_ClockInitStruct->USART_CPHA = USART_CPHA_1Edge;
  USART_ClockInitStruct->USART_LastBit = USART_LastBit_Disable;
}

/**
  * @brief  Enables or disables the specified USART peripheral.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  NewState: new state of the USARTx peripheral.
  *         This parameter can be: ENABLE or DISABLE.
  * @retval None.
  */
void USART_Cmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  if (NewState != DISABLE)
  {
    /* Enable the selected USART by setting the UE bit in the CR1 register */
    USARTx->CR1 |= USART_CR1_UE;
  }
  else
  {
    /* Disable the selected USART by clearing the UE bit in the CR1 register */
    USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_UE);
  }
}

/**
  * @brief  Sets the system clock prescaler.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_Prescaler: specifies the prescaler clock. 
  * @note   The function is used for IrDA mode with UART4 and UART5.   
  * @retval None.
  */
void USART_SetPrescaler(USART_TypeDef* USARTx, uint8_t USART_Prescaler)
{ 
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  
  /* Clear the USART prescaler */
  USARTx->GTPR &= USART_GTPR_GT;
  /* Set the USART prescaler */
  USARTx->GTPR |= USART_Prescaler;
}

/**
  * @brief  Enables or disables the USART's 8x oversampling mode.
  * @param USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *     USART1, USART2, USART3, UART4 or UART5.
  * @param NewState: new state of the USART 8x oversampling mode.
  *   This parameter can be: ENABLE or DISABLE.
  *
  * @note
  *   This function has to be called before calling USART_Init()
  *   function in order to have correct baudrate Divider value.
  * @retval None
  */
void USART_OverSampling8Cmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  if (NewState != DISABLE)
  {
    /* Enable the 8x Oversampling mode by setting the OVER8 bit in the CR1 register */
    USARTx->CR1 |= USART_CR1_OVER8;
  }
  else
  {
    /* Disable the 8x Oversampling mode by clearing the OVER8 bit in the CR1 register */
    USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_OVER8);
  }
}  

/**
  * @brief  Enables or disables the USART's one bit sampling method.
  * @param USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param NewState: new state of the USART one bit sampling method.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None.
  */
void USART_OneBitMethodCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  if (NewState != DISABLE)
  {
    /* Enable the one bit method by setting the ONEBITE bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_ONEBIT;
  }
  else
  {
    /* Disable the one bit method by clearing the ONEBITE bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_ONEBIT);
  }
}

/**
  * @}
  */

/** @defgroup USART_Group2 Data transfers functions
 *  @brief   Data transfers functions 
 *
@verbatim
 ===============================================================================
                    ##### Data transfers functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage 
         the USART data transfers.
    [..] During an USART reception, data shifts in least significant bit first 
         through the RX pin. In this mode, the USART_DR register consists of 
         a buffer (RDR) between the internal bus and the received shift register.
         When a transmission is taking place, a write instruction to 
         the USART_DR register stores the data in the TDR register and which is 
         copied in the shift register at the end of the current transmission.
    [..] The read access of the USART_DR register can be done using 
         the USART_ReceiveData() function and returns the RDR buffered value.
        Whereas a write access to the USART_DR can be done using USART_SendData()
        function and stores the written data into TDR buffer.

@endverbatim
  * @{
  */

/**
  * @brief  Transmits single data through the USARTx peripheral.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  Data: the data to transmit.
  * @retval None.
  */
void USART_SendData(USART_TypeDef* USARTx, uint16_t Data)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DATA(Data)); 
    
  /* Transmit Data */
  USARTx->DR = (Data & (uint16_t)0x01FF);
}

/**
  * @brief  Returns the most recent received data by the USARTx peripheral.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @retval The received data.
  */
uint16_t USART_ReceiveData(USART_TypeDef* USARTx)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  
  /* Receive Data */
  return (uint16_t)(USARTx->DR & (uint16_t)0x01FF);
}

/**
  * @}
  */

/** @defgroup USART_Group3 MultiProcessor Communication functions
 *  @brief   Multi-Processor Communication functions 
 *
@verbatim
 ===============================================================================
             ##### Multi-Processor Communication functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage the USART 
         multiprocessor communication.
    [..] For instance one of the USARTs can be the master, its TX output is
         connected to the RX input of the other USART. The others are slaves,
         their respective TX outputs are logically ANDed together and connected 
         to the RX input of the master. USART multiprocessor communication is 
         possible through the following procedure:
         (#) Program the Baud rate, Word length = 9 bits, Stop bits, Parity, 
             Mode transmitter or Mode receiver and hardware flow control values 
             using the USART_Init() function.
         (#) Configures the USART address using the USART_SetAddress() function.
         (#) Configures the wake up methode (USART_WakeUp_IdleLine or 
             USART_WakeUp_AddressMark) using USART_WakeUpConfig() function only 
             for the slaves.
         (#) Enable the USART using the USART_Cmd() function.
         (#) Enter the USART slaves in mute mode using USART_ReceiverWakeUpCmd() 
             function.

    [..] The USART Slave exit from mute mode when receive the wake up condition.

@endverbatim
  * @{
  */

/**
  * @brief  Sets the address of the USART node.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_Address: Indicates the address of the USART node.
  * @retval None
  */
void USART_SetAddress(USART_TypeDef* USARTx, uint8_t USART_Address)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_ADDRESS(USART_Address)); 
    
  /* Clear the USART address */
  USARTx->CR2 &= (uint16_t)~((uint16_t)USART_CR2_ADD);
  /* Set the USART address node */
  USARTx->CR2 |= USART_Address;
}

/**
  * @brief  Determines if the USART is in mute mode or not.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  NewState: new state of the USART mute mode.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_ReceiverWakeUpCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState)); 
  
  if (NewState != DISABLE)
  {
    /* Enable the USART mute mode  by setting the RWU bit in the CR1 register */
    USARTx->CR1 |= USART_CR1_RWU;
  }
  else
  {
    /* Disable the USART mute mode by clearing the RWU bit in the CR1 register */
    USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_RWU);
  }
}
/**
  * @brief  Selects the USART WakeUp method.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_WakeUp: specifies the USART wakeup method.
  *   This parameter can be one of the following values:
  *     @arg USART_WakeUp_IdleLine: WakeUp by an idle line detection.
  *     @arg USART_WakeUp_AddressMark: WakeUp by an address mark.
  * @retval None.
  */
void USART_WakeUpConfig(USART_TypeDef* USARTx, uint16_t USART_WakeUp)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_WAKEUP(USART_WakeUp));
  
  USARTx->CR1 &= (uint16_t)~((uint16_t)USART_CR1_WAKE);
  USARTx->CR1 |= USART_WakeUp;
}

/**
  * @}
  */

/** @defgroup USART_Group4 LIN mode functions
 *  @brief   LIN mode functions 
 *
@verbatim
 ===============================================================================
                       ##### LIN mode functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage the USART 
         LIN Mode communication.
    [..] In LIN mode, 8-bit data format with 1 stop bit is required in accordance 
         with the LIN standard.
    [..] Only this LIN Feature is supported by the USART IP:
         (+) LIN Master Synchronous Break send capability and LIN slave break 
             detection capability :  13-bit break generation and 10/11 bit break 
             detection.
    [..] USART LIN Master transmitter communication is possible through the 
         following procedure:
         (#) Program the Baud rate, Word length = 8bits, Stop bits = 1bit, Parity, 
             Mode transmitter or Mode receiver and hardware flow control values 
             using the USART_Init() function.
         (#) Enable the USART using the USART_Cmd() function.
         (#) Enable the LIN mode using the USART_LINCmd() function.
         (#) Send the break character using USART_SendBreak() function.
    [..] USART LIN Master receiver communication is possible through the 
         following procedure:
         (#) Program the Baud rate, Word length = 8bits, Stop bits = 1bit, Parity, 
             Mode transmitter or Mode receiver and hardware flow control values 
            using the USART_Init() function.
         (#) Enable the USART using the USART_Cmd() function.
         (#) Configures the break detection length 
             using the USART_LINBreakDetectLengthConfig() function.
         (#) Enable the LIN mode using the USART_LINCmd() function.
         -@- In LIN mode, the following bits must be kept cleared:
             (+@) CLKEN in the USART_CR2 register.
             (+@) STOP[1:0], SCEN, HDSEL and IREN in the USART_CR3 register.

@endverbatim
  * @{
  */

/**
  * @brief  Sets the USART LIN Break detection length.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_LINBreakDetectLength: specifies the LIN break detection length.
  *   This parameter can be one of the following values:
  *     @arg USART_LINBreakDetectLength_10b: 10-bit break detection.
  *     @arg USART_LINBreakDetectLength_11b: 11-bit break detection.
  * @retval None.
  */
void USART_LINBreakDetectLengthConfig(USART_TypeDef* USARTx, uint16_t USART_LINBreakDetectLength)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_LIN_BREAK_DETECT_LENGTH(USART_LINBreakDetectLength));
  
  USARTx->CR2 &= (uint16_t)~((uint16_t)USART_CR2_LBDL);
  USARTx->CR2 |= USART_LINBreakDetectLength;  
}

/**
  * @brief  Enables or disables the USART's LIN mode.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  NewState: new state of the USART LIN mode.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None.
  */
void USART_LINCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  if (NewState != DISABLE)
  {
    /* Enable the LIN mode by setting the LINEN bit in the CR2 register */
    USARTx->CR2 |= USART_CR2_LINEN;
  }
  else
  {
    /* Disable the LIN mode by clearing the LINEN bit in the CR2 register */
    USARTx->CR2 &= (uint16_t)~((uint16_t)USART_CR2_LINEN);
  }
}

/**
  * @brief  Transmits break characters.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @retval None.
  */
void USART_SendBreak(USART_TypeDef* USARTx)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  
  /* Send break characters */
  USARTx->CR1 |= USART_CR1_SBK;
}

/**
  * @}
  */

/** @defgroup USART_Group5 Halfduplex mode function
 *  @brief   Half-duplex mode function 
 *
@verbatim
 ===============================================================================
                   ##### Half-duplex mode function #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage the USART
         Half-duplex communication.
    [..] The USART can be configured to follow a single-wire half-duplex protocol 
         where the TX and RX lines are internally connected.
    [..] USART Half duplex communication is possible through the following procedure:
         (#) Program the Baud rate, Word length, Stop bits, Parity, Mode transmitter 
             or Mode receiver and hardware flow control values using the USART_Init()
            function.
         (#) Configures the USART address using the USART_SetAddress() function.
         (#) Enable the USART using the USART_Cmd() function.
         (#) Enable the half duplex mode using USART_HalfDuplexCmd() function.
         -@- The RX pin is no longer used.
         -@- In Half-duplex mode the following bits must be kept cleared:
             (+@) LINEN and CLKEN bits in the USART_CR2 register.
             (+@) SCEN and IREN bits in the USART_CR3 register.

@endverbatim
  * @{
  */

/**
  * @brief  Enables or disables the USART's Half Duplex communication.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  NewState: new state of the USART Communication.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_HalfDuplexCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  
  if (NewState != DISABLE)
  {
    /* Enable the Half-Duplex mode by setting the HDSEL bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_HDSEL;
  }
  else
  {
    /* Disable the Half-Duplex mode by clearing the HDSEL bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_HDSEL);
  }
}

/**
  * @}
  */


/** @defgroup USART_Group6 Smartcard mode functions
 *  @brief   Smartcard mode functions 
 *
@verbatim
 ===============================================================================
                     ##### Smartcard mode functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage the USART 
         Smartcard communication.
    [..] The Smartcard interface is designed to support asynchronous protocol 
         Smartcards as defined in the ISO 7816-3 standard. The USART can provide 
         a clock to the smartcard through the SCLK output. In smartcard mode, 
         SCLK is not associated to the communication but is simply derived from 
         the internal peripheral input clock through a 5-bit prescaler.
    [..] Smartcard communication is possible through the following procedure:
         (#) Configures the Smartcard Prsecaler using the USART_SetPrescaler() 
             function.
         (#) Configures the Smartcard Guard Time using the USART_SetGuardTime() 
             function.
         (#) Program the USART clock using the USART_ClockInit() function as following:
             (++) USART Clock enabled.
             (++) USART CPOL Low.
             (++) USART CPHA on first edge.
             (++) USART Last Bit Clock Enabled.
         (#) Program the Smartcard interface using the USART_Init() function as 
             following:
             (++) Word Length = 9 Bits.
             (++) 1.5 Stop Bit.
             (++) Even parity.
             (++) BaudRate = 12096 baud.
             (++) Hardware flow control disabled (RTS and CTS signals).
             (++) Tx and Rx enabled
         (#) Optionally you can enable the parity error interrupt using 
             the USART_ITConfig() function.
         (#) Enable the USART using the USART_Cmd() function.
         (#) Enable the Smartcard NACK using the USART_SmartCardNACKCmd() function.
         (#) Enable the Smartcard interface using the USART_SmartCardCmd() function.
    [..] 
  Please refer to the ISO 7816-3 specification for more details.
    [..] 
         (@) It is also possible to choose 0.5 stop bit for receiving but it is 
             recommended to use 1.5 stop bits for both transmitting and receiving 
             to avoid switching between the two configurations.
         (@) In smartcard mode, the following bits must be kept cleared:
             (+@) LINEN bit in the USART_CR2 register.
             (+@) HDSEL and IREN bits in the USART_CR3 register.

@endverbatim
  * @{
  */

/**
  * @brief  Sets the specified USART guard time.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2 or USART3.
  * @param  USART_GuardTime: specifies the guard time.   
  * @retval None.
  */
void USART_SetGuardTime(USART_TypeDef* USARTx, uint8_t USART_GuardTime)
{    
  /* Check the parameters */
  assert_param(IS_USART_123_PERIPH(USARTx));
  
  /* Clear the USART Guard time */
  USARTx->GTPR &= USART_GTPR_PSC;
  /* Set the USART guard time */
  USARTx->GTPR |= (uint16_t)((uint16_t)USART_GuardTime << 0x08);
}

/**
  * @brief  Enables or disables the USART's Smart Card mode.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2 or USART3.
  * @param  NewState: new state of the Smart Card mode.
  *   This parameter can be: ENABLE or DISABLE.      
  * @retval None
  */
void USART_SmartCardCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_123_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the SC mode by setting the SCEN bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_SCEN;
  }
  else
  {
    /* Disable the SC mode by clearing the SCEN bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_SCEN);
  }
}

/**
  * @brief  Enables or disables NACK transmission.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2 or USART3.
  * @param  NewState: new state of the NACK transmission.
  *   This parameter can be: ENABLE or DISABLE.  
  * @retval None.
  */
void USART_SmartCardNACKCmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_123_PERIPH(USARTx)); 
  assert_param(IS_FUNCTIONAL_STATE(NewState));
  if (NewState != DISABLE)
  {
    /* Enable the NACK transmission by setting the NACK bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_NACK;
  }
  else
  {
    /* Disable the NACK transmission by clearing the NACK bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_NACK);
  }
}

/**
  * @}
  */

/** @defgroup USART_Group7 IrDA mode functions
 *  @brief   IrDA mode functions 
 *
@verbatim
 ===============================================================================
                        ##### IrDA mode functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to manage the USART 
         IrDA communication.
    [..] IrDA is a half duplex communication protocol. If the Transmitter is busy, 
         any data on the IrDA receive line will be ignored by the IrDA decoder 
         and if the Receiver is busy, data on the TX from the USART to IrDA will 
         not be encoded by IrDA. While receiving data, transmission should be 
         avoided as the data to be transmitted could be corrupted.

    [..] IrDA communication is possible through the following procedure:
         (#) Program the Baud rate, Word length = 8 bits, Stop bits, Parity, 
             Transmitter/Receiver modes and hardware flow control values using 
             the USART_Init() function.
         (#) Enable the USART using the USART_Cmd() function.
         (#) Configures the IrDA pulse width by configuring the prescaler using  
             the USART_SetPrescaler() function.
         (#) Configures the IrDA  USART_IrDAMode_LowPower or USART_IrDAMode_Normal 
             mode using the USART_IrDAConfig() function.
         (#) Enable the IrDA using the USART_IrDACmd() function.

    [..]
    (@) A pulse of width less than two and greater than one PSC period(s) may or 
        may not be rejected.
    (@) The receiver set up time should be managed by software. The IrDA physical 
        layer specification specifies a minimum of 10 ms delay between 
        transmission and reception (IrDA is a half duplex protocol).
    (@) In IrDA mode, the following bits must be kept cleared:
        (+@) LINEN, STOP and CLKEN bits in the USART_CR2 register.
        (+@) SCEN and HDSEL bits in the USART_CR3 register.

@endverbatim
  * @{
  */

/**
  * @brief  Configures the USART's IrDA interface.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_IrDAMode: specifies the IrDA mode.
  *   This parameter can be one of the following values:
  *     @arg USART_IrDAMode_LowPower: USART IrDA Low Power mode selected.
  *     @arg USART_IrDAMode_Normal: USART IrDA Normal mode selected.
  * @retval None
  */
void USART_IrDAConfig(USART_TypeDef* USARTx, uint16_t USART_IrDAMode)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_IRDA_MODE(USART_IrDAMode));
    
  USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_IRLP);
  USARTx->CR3 |= USART_IrDAMode;
}

/**
  * @brief  Enables or disables the USART's IrDA interface.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  NewState: new state of the IrDA mode.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None
  */
void USART_IrDACmd(USART_TypeDef* USARTx, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_FUNCTIONAL_STATE(NewState));
    
  if (NewState != DISABLE)
  {
    /* Enable the IrDA mode by setting the IREN bit in the CR3 register */
    USARTx->CR3 |= USART_CR3_IREN;
  }
  else
  {
    /* Disable the IrDA mode by clearing the IREN bit in the CR3 register */
    USARTx->CR3 &= (uint16_t)~((uint16_t)USART_CR3_IREN);
  }
}

/**
  * @}
  */

/** @defgroup USART_Group8 DMA transfers management functions
 *  @brief   DMA transfers management functions
 *
@verbatim
 ===============================================================================
               ##### DMA transfers management functions #####
 ===============================================================================

@endverbatim
  * @{
  */
  
/**
  * @brief  Enables or disables the USART's DMA interface.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_DMAReq: specifies the DMA request.
  *   This parameter can be any combination of the following values:
  *     @arg USART_DMAReq_Tx: USART DMA transmit request.
  *     @arg USART_DMAReq_Rx: USART DMA receive request.
  * @param  NewState: new state of the DMA Request sources.
  *   This parameter can be: ENABLE or DISABLE.   
  * @retval None
  */
void USART_DMACmd(USART_TypeDef* USARTx, uint16_t USART_DMAReq, FunctionalState NewState)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_DMAREQ(USART_DMAReq));  
  assert_param(IS_FUNCTIONAL_STATE(NewState)); 

  if (NewState != DISABLE)
  {
    /* Enable the DMA transfer for selected requests by setting the DMAT and/or
       DMAR bits in the USART CR3 register */
    USARTx->CR3 |= USART_DMAReq;
  }
  else
  {
    /* Disable the DMA transfer for selected requests by clearing the DMAT and/or
       DMAR bits in the USART CR3 register */
    USARTx->CR3 &= (uint16_t)~USART_DMAReq;
  }
}

/**
  * @}
  */
  
/** @defgroup USART_Group9 Interrupts and flags management functions
 *  @brief   Interrupts and flags management functions 
 *
@verbatim
 ===============================================================================
            ##### Interrupts and flags management functions #####
 ===============================================================================
    [..] This subsection provides a set of functions allowing to configure the 
         USART Interrupts sources, DMA channels requests and check or clear the 
         flags or pending bits status. The user should identify which mode will 
         be used in his application to manage the communication: Polling mode, 
         Interrupt mode or DMA mode.
 *** Polling Mode ***
 ====================
    [..] In Polling Mode, the SPI communication can be managed by 10 flags:
         (#) USART_FLAG_TXE: to indicate the status of the transmit buffer register.
         (#) USART_FLAG_RXNE: to indicate the status of the receive buffer register.
         (#) USART_FLAG_TC: to indicate the status of the transmit operation.
         (#) USART_FLAG_IDLE: to indicate the status of the Idle Line.
         (#) USART_FLAG_CTS: to indicate the status of the nCTS input.
         (#) USART_FLAG_LBD: to indicate the status of the LIN break detection.
         (#) USART_FLAG_NE: to indicate if a noise error occur.
         (#) USART_FLAG_FE: to indicate if a frame error occur.
         (#) USART_FLAG_PE: to indicate if a parity error occur.
         (#) USART_FLAG_ORE: to indicate if an Overrun error occur.
    [..] In this Mode it is advised to use the following functions:
         (+) FlagStatus USART_GetFlagStatus(USART_TypeDef* USARTx, uint16_t USART_FLAG).
         (+) void USART_ClearFlag(USART_TypeDef* USARTx, uint16_t USART_FLAG).
  
 *** Interrupt Mode ***
 ======================
    [..] In Interrupt Mode, the USART communication can be managed by 8 interrupt 
         sources and 10 pending bits:
         (+) Pending Bits:
             (##) USART_IT_TXE: to indicate the status of the transmit buffer 
                  register.
             (##) USART_IT_RXNE: to indicate the status of the receive buffer 
                  register.
             (##) USART_IT_TC: to indicate the status of the transmit operation.
             (##) USART_IT_IDLE: to indicate the status of the Idle Line.
             (##) USART_IT_CTS: to indicate the status of the nCTS input.
             (##) USART_IT_LBD: to indicate the status of the LIN break detection.
             (##) USART_IT_NE: to indicate if a noise error occur.
             (##) USART_IT_FE: to indicate if a frame error occur.
             (##) USART_IT_PE: to indicate if a parity error occur.
             (##) USART_IT_ORE: to indicate if an Overrun error occur
                  (if the RXNEIE or EIE bits are set).

         (+) Interrupt Source:
             (##) USART_IT_TXE: specifies the interrupt source for the Tx buffer 
                  empty interrupt. 
             (##) USART_IT_RXNE: specifies the interrupt source for the Rx buffer 
                  not empty interrupt.
             (##) USART_IT_TC: specifies the interrupt source for the Transmit 
                  complete interrupt. 
             (##) USART_IT_IDLE: specifies the interrupt source for the Idle Line 
                  interrupt.
             (##) USART_IT_CTS: specifies the interrupt source for the CTS interrupt. 
             (##) USART_IT_LBD: specifies the interrupt source for the LIN break 
                  detection interrupt. 
             (##) USART_IT_PE: specifies the interrupt source for theparity error 
                  interrupt. 
             (##) USART_IT_ERR:  specifies the interrupt source for the errors 
                  interrupt.
             -@@- Some parameters are coded in order to use them as interrupt 
                 source or as pending bits.
    [..] In this Mode it is advised to use the following functions:
         (+) void USART_ITConfig(USART_TypeDef* USARTx, uint16_t USART_IT, 
             FunctionalState NewState).
         (+) ITStatus USART_GetITStatus(USART_TypeDef* USARTx, uint16_t USART_IT).
         (+) void USART_ClearITPendingBit(USART_TypeDef* USARTx, uint16_t USART_IT).
  
 *** DMA Mode ***
 ================
    [..] In DMA Mode, the USART communication can be managed by 2 DMA Channel 
         requests:
         (#) USART_DMAReq_Tx: specifies the Tx buffer DMA transfer request.
         (#) USART_DMAReq_Rx: specifies the Rx buffer DMA transfer request.
    [..] In this Mode it is advised to use the following function:
         (+) void USART_DMACmd(USART_TypeDef* USARTx, uint16_t USART_DMAReq, 
             FunctionalState NewState).
@endverbatim
  * @{
  */

/**
  * @brief  Enables or disables the specified USART interrupts.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_IT: specifies the USART interrupt sources to be enabled or disabled.
  *   This parameter can be one of the following values:
  *     @arg USART_IT_CTS:  CTS change interrupt.
  *     @arg USART_IT_LBD:  LIN Break detection interrupt.
  *     @arg USART_IT_TXE:  Tansmit Data Register empty interrupt.
  *     @arg USART_IT_TC:   Transmission complete interrupt.
  *     @arg USART_IT_RXNE: Receive Data register not empty interrupt.
  *     @arg USART_IT_IDLE: Idle line detection interrupt.
  *     @arg USART_IT_PE:   Parity Error interrupt.
  *     @arg USART_IT_ERR:  Error interrupt(Frame error, noise error, overrun error).
  * @param  NewState: new state of the specified USARTx interrupts.
  *   This parameter can be: ENABLE or DISABLE.
  * @retval None.
  */
void USART_ITConfig(USART_TypeDef* USARTx, uint16_t USART_IT, FunctionalState NewState)
{
  uint32_t usartreg = 0x00, itpos = 0x00, itmask = 0x00;
  uint32_t usartxbase = 0x00;
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_CONFIG_IT(USART_IT));
  assert_param(IS_FUNCTIONAL_STATE(NewState));

  /* The CTS interrupt is not available for UART4 and UART5 */
  if (USART_IT == USART_IT_CTS)
  {
    assert_param(IS_USART_123_PERIPH(USARTx));
  } 
    
  usartxbase = (uint32_t)USARTx;

  /* Get the USART register index */
  usartreg = (((uint8_t)USART_IT) >> 0x05);

  /* Get the interrupt position */
  itpos = USART_IT & IT_MASK;
  itmask = (((uint32_t)0x01) << itpos);
    
  if (usartreg == 0x01) /* The IT is in CR1 register */
  {
    usartxbase += 0x0C;
  }
  else if (usartreg == 0x02) /* The IT is in CR2 register */
  {
    usartxbase += 0x10;
  }
  else /* The IT is in CR3 register */
  {
    usartxbase += 0x14; 
  }
  if (NewState != DISABLE)
  {
    *(__IO uint32_t*)usartxbase  |= itmask;
  }
  else
  {
    *(__IO uint32_t*)usartxbase &= ~itmask;
  }
}

/**
  * @brief  Checks whether the specified USART flag is set or not.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_FLAG: specifies the flag to check.
  *   This parameter can be one of the following values:
  *     @arg USART_FLAG_CTS:  CTS Change flag (not available for UART4 and UART5).
  *     @arg USART_FLAG_LBD:  LIN Break detection flag.
  *     @arg USART_FLAG_TXE:  Transmit data register empty flag.
  *     @arg USART_FLAG_TC:   Transmission Complete flag.
  *     @arg USART_FLAG_RXNE: Receive data register not empty flag.
  *     @arg USART_FLAG_IDLE: Idle Line detection flag.
  *     @arg USART_FLAG_ORE:  OverRun Error flag.
  *     @arg USART_FLAG_NE:   Noise Error flag.
  *     @arg USART_FLAG_FE:   Framing Error flag.
  *     @arg USART_FLAG_PE:   Parity Error flag.
  * @retval The new state of USART_FLAG (SET or RESET).
  */
FlagStatus USART_GetFlagStatus(USART_TypeDef* USARTx, uint16_t USART_FLAG)
{
  FlagStatus bitstatus = RESET;
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_FLAG(USART_FLAG));

  /* The CTS flag is not available for UART4 and UART5 */
  if (USART_FLAG == USART_FLAG_CTS)
  {
    assert_param(IS_USART_123_PERIPH(USARTx));
  } 
    
  if ((USARTx->SR & USART_FLAG) != (uint16_t)RESET)
  {
    bitstatus = SET;
  }
  else
  {
    bitstatus = RESET;
  }
  return bitstatus;
}

/**
  * @brief  Clears the USARTx's pending flags.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_FLAG: specifies the flag to clear.
  *   This parameter can be any combination of the following values:
  *     @arg USART_FLAG_CTS:  CTS Change flag (not available for UART4 and UART5).
  *     @arg USART_FLAG_LBD:  LIN Break detection flag.
  *     @arg USART_FLAG_TC:   Transmission Complete flag.
  *     @arg USART_FLAG_RXNE: Receive data register not empty flag.
  *   
  *
  * @note PE (Parity error), FE (Framing error), NE (Noise error), ORE (OverRun 
  *     error) and IDLE (Idle line detected) flags are cleared by software 
  *     sequence: a read operation to USART_SR register (USART_GetFlagStatus()) 
  *     followed by a read operation to USART_DR register (USART_ReceiveData()).
  * @note RXNE flag can be also cleared by a read to the USART_DR register 
  *     (USART_ReceiveData()).
  * @note TC flag can be also cleared by software sequence: a read operation to 
  *     USART_SR register (USART_GetFlagStatus()) followed by a write operation
  *     to USART_DR register (USART_SendData()).
  * @note TXE flag is cleared only by a write to the USART_DR register 
  *     (USART_SendData()).
  * @retval None
  */
void USART_ClearFlag(USART_TypeDef* USARTx, uint16_t USART_FLAG)
{
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_CLEAR_FLAG(USART_FLAG));

  /* The CTS flag is not available for UART4 and UART5 */
  if ((USART_FLAG & USART_FLAG_CTS) == USART_FLAG_CTS)
  {
    assert_param(IS_USART_123_PERIPH(USARTx));
  } 
       
  USARTx->SR = (uint16_t)~USART_FLAG;
}

/**
  * @brief  Checks whether the specified USART interrupt has occurred or not.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_IT: specifies the USART interrupt source to check.
  *   This parameter can be one of the following values:
  *     @arg USART_IT_CTS:  CTS change interrupt (not available for UART4 and UART5)
  *     @arg USART_IT_LBD:  LIN Break detection interrupt
  *     @arg USART_IT_TXE:  Tansmit Data Register empty interrupt
  *     @arg USART_IT_TC:   Transmission complete interrupt
  *     @arg USART_IT_RXNE: Receive Data register not empty interrupt
  *     @arg USART_IT_IDLE: Idle line detection interrupt
  *     @arg USART_IT_ORE_RX: OverRun Error interrupt if the RXNEIE bit is set.
  *     @arg USART_IT_ORE_ER: OverRun Error interrupt if the EIE bit is set.   
  *     @arg USART_IT_NE:   Noise Error interrupt
  *     @arg USART_IT_FE:   Framing Error interrupt
  *     @arg USART_IT_PE:   Parity Error interrupt
  * @retval The new state of USART_IT (SET or RESET).
  */
ITStatus USART_GetITStatus(USART_TypeDef* USARTx, uint16_t USART_IT)
{
  uint32_t bitpos = 0x00, itmask = 0x00, usartreg = 0x00;
  ITStatus bitstatus = RESET;
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_GET_IT(USART_IT)); 

  /* The CTS interrupt is not available for UART4 and UART5 */ 
  if (USART_IT == USART_IT_CTS)
  {
    assert_param(IS_USART_123_PERIPH(USARTx));
  } 
    
  /* Get the USART register index */
  usartreg = (((uint8_t)USART_IT) >> 0x05);
  /* Get the interrupt position */
  itmask = USART_IT & IT_MASK;
  itmask = (uint32_t)0x01 << itmask;
  
  if (usartreg == 0x01) /* The IT  is in CR1 register */
  {
    itmask &= USARTx->CR1;
  }
  else if (usartreg == 0x02) /* The IT  is in CR2 register */
  {
    itmask &= USARTx->CR2;
  }
  else /* The IT  is in CR3 register */
  {
    itmask &= USARTx->CR3;
  }
  
  bitpos = USART_IT >> 0x08;
  bitpos = (uint32_t)0x01 << bitpos;
  bitpos &= USARTx->SR;
  if ((itmask != (uint16_t)RESET)&&(bitpos != (uint16_t)RESET))
  {
    bitstatus = SET;
  }
  else
  {
    bitstatus = RESET;
  }
  
  return bitstatus;  
}

/**
  * @brief  Clears the USARTx's interrupt pending bits.
  * @param  USARTx: Select the USART peripheral. 
  *   This parameter can be one of the following values:
  *   USART1, USART2, USART3, UART4 or UART5.
  * @param  USART_IT: specifies the interrupt pending bit to clear.
  *   This parameter can be one of the following values:
  *     @arg USART_IT_CTS:  CTS change interrupt (not available for UART4 and UART5)
  *     @arg USART_IT_LBD:  LIN Break detection interrupt
  *     @arg USART_IT_TC:   Transmission complete interrupt. 
  *     @arg USART_IT_RXNE: Receive Data register not empty interrupt.
  *   

  * @note PE (Parity error), FE (Framing error), NE (Noise error), ORE (OverRun 
  *     error) and IDLE (Idle line detected) pending bits are cleared by 
  *     software sequence: a read operation to USART_SR register 
  *     (USART_GetITStatus()) followed by a read operation to USART_DR register 
  *     (USART_ReceiveData()).
  * @note RXNE pending bit can be also cleared by a read to the USART_DR register 
  *     (USART_ReceiveData()).
  * @note TC pending bit can be also cleared by software sequence: a read 
  *     operation to USART_SR register (USART_GetITStatus()) followed by a write 
  *     operation to USART_DR register (USART_SendData()).
  * @note TXE pending bit is cleared only by a write to the USART_DR register 
  *     (USART_SendData()).
  * @retval None
  */
void USART_ClearITPendingBit(USART_TypeDef* USARTx, uint16_t USART_IT)
{
  uint16_t bitpos = 0x00, itmask = 0x00;
  /* Check the parameters */
  assert_param(IS_USART_ALL_PERIPH(USARTx));
  assert_param(IS_USART_CLEAR_IT(USART_IT)); 

  /* The CTS interrupt is not available for UART4 and UART5 */
  if (USART_IT == USART_IT_CTS)
  {
    assert_param(IS_USART_123_PERIPH(USARTx));
  } 
    
  bitpos = USART_IT >> 0x08;
  itmask = ((uint16_t)0x01 << (uint16_t)bitpos);
  USARTx->SR = (uint16_t)~itmask;
}

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/**
  * @}
  */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/