// // GPS: communicate with ublox GPS module via ubx protocol // #include "stm32f0xx_hal.h" #include "config.h" #include "error.h" #include "system/gpio.h" #include "system/uart.h" #include "gps.h" volatile gps_data_t position; uint8_t gpson = 0; // Private methods static void gps_ubx_checksum(uint8_t* data, uint8_t len, uint8_t* cka, uint8_t* ckb); static uint8_t _gps_verify_checksum(uint8_t* data, uint8_t len); // Poll for fix data from the GPS and update the internal structure void gps_update_data(void) { // Error! if(!gpson) { error_assert(ERR_GPS_OFF); return; } // Construct the request to the GPS uint8_t request[8] = {0xB5, 0x62, 0x01, 0x07, 0x00, 0x00, 0xFF, 0xFF}; volatile uint8_t check_a = 0; volatile uint8_t check_b = 0; for(uint8_t i = 2; i<6; i++) { check_a += request[i]; check_b += check_a; } request[6] = check_a; request[7] = check_b; volatile uint8_t flushed = uart_gethandle()->Instance->RDR; HAL_UART_Transmit(uart_gethandle(), request, 8, 100); // Get the message back from the GPS uint8_t buf[100]; for(uint8_t i=0; i<100; i++) buf[i] = 0xaa; volatile HAL_StatusTypeDef res = HAL_UART_Receive(uart_gethandle(), buf, 100, 3000); // Check 60 bytes minus SYNC and CHECKSUM (4 bytes) if( !_gps_verify_checksum(&buf[2], 96) ) { error_assert(ERR_GPS_CHECKSUM); } //volatile uint32_t gpstime_ms = (buf[6+0] << 24) | (buf[6+1] << 16) | buf[6+2] << 8) | (buf[6+3]); position.month = buf[6+6]; position.day = buf[6+7]; position.hour = buf[6+8]; position.minute = buf[6+9]; position.second = buf[6+10]; position.valid = buf[6+11] & 0b1111; position.fixtype = buf[6+20]; position.sats_in_solution = buf[6+23]; position.longitude = (buf[6+24] << 0) | (buf[6+25] << 8) | (buf[6+26] << 16) | (buf[6+27] << 24); // degrees position.latitude = (buf[6+28] << 0) | (buf[6+29] << 8) | (buf[6+30] << 16) | (buf[6+31] << 24); // degrees position.altitude = (buf[6+36] << 0) | (buf[6+37] << 8) | (buf[6+38] << 16) | (buf[6+39] << 24); // mm above sealevel position.altitude /= 1000; // mm => m position.speed = (buf[6+60] << 0) | (buf[6+61] << 8) | (buf[6+62] << 16) | (buf[6+63] << 24); // mm/second position.speed /= 10; // mm/s -> cm/s position.pdop = (buf[6+76] << 0) | (buf[6+77] << 8); position.pdop /= 100; // scale to dop units position.heading = (buf[6+64] << 0) | (buf[6+65] << 8) | (buf[6+66] << 16) | (buf[6+67] << 24); position.heading /= 100000; // 1e-5 // // Return the value if GPSfixOK is set in 'flags' // if( buf[17] & 0x01 ) // *lock = buf[16]; // else // *lock = 0; } // Verify the checksum for the given data and length. static uint8_t _gps_verify_checksum(uint8_t* data, uint8_t len) { uint8_t a, b; gps_ubx_checksum(data, len, &a, &b); if( a != *(data + len) || b != *(data + len + 1)) return 0; else return 1; } // Calculate a UBX checksum using 8-bit Fletcher (RFC1145) static void gps_ubx_checksum(uint8_t* data, uint8_t len, uint8_t* cka, uint8_t* ckb) { *cka = 0; *ckb = 0; for( uint8_t i = 0; i < len; i++ ) { *cka += *data; *ckb += *cka; data++; } } // Power on GPS module and initialize UART void gps_poweron(void) { // NOTE: pchannel HAL_GPIO_WritePin(GPS_NOTEN, 0); uart_init(); // Disable messages uint8_t setGGA[] = {0XB5, 0X62, 0X06, 0X01, 0X08, 0X00, 0XF0, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0XFF, 0X23}; HAL_UART_Transmit(uart_gethandle(), setGGA, sizeof(setGGA)/sizeof(uint8_t), 100); HAL_Delay(100); uint8_t ackbuffer[10]; for(uint8_t i=0; i<10; i++) ackbuffer[i] = 0xaa; HAL_UART_Receive(uart_gethandle(), ackbuffer, 10, 100); uint8_t setZDA[] = {0XB5, 0X62, 0X06, 0X01, 0X08, 0X00, 0XF0, 0X08, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X07, 0X5B}; HAL_UART_Transmit(uart_gethandle(), setZDA, sizeof(setZDA)/sizeof(uint8_t), 100); HAL_Delay(100); uint8_t setGLL[] = {0XB5, 0X62, 0X06, 0X01, 0X08, 0X00, 0XF0, 0X01, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X2A}; HAL_UART_Transmit(uart_gethandle(), setGLL, sizeof(setGLL)/sizeof(uint8_t), 100); HAL_Delay(100); uint8_t setGSA[] = {0XB5, 0X62, 0X06, 0X01, 0X08, 0X00, 0XF0, 0X02, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X01, 0X31}; HAL_UART_Transmit(uart_gethandle(), setGSA, sizeof(setGSA)/sizeof(uint8_t), 100); HAL_Delay(100); uint8_t setGSV[] = {0XB5, 0X62, 0X06, 0X01, 0X08, 0X00, 0XF0, 0X03, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X02, 0X38}; HAL_UART_Transmit(uart_gethandle(), setGSV, sizeof(setGSV)/sizeof(uint8_t), 100); HAL_Delay(100); uint8_t setRMC[] = {0XB5, 0X62, 0X06, 0X01, 0X08, 0X00, 0XF0, 0X04, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X03, 0X3F}; HAL_UART_Transmit(uart_gethandle(), setRMC, sizeof(setRMC)/sizeof(uint8_t), 100); HAL_Delay(100); uint8_t setVTG[] = {0XB5, 0X62, 0X06, 0X01, 0X08, 0X00, 0XF0, 0X05, 0X00, 0X00, 0X00, 0X00, 0X00, 0X00, 0X04, 0X46}; HAL_UART_Transmit(uart_gethandle(), setVTG, sizeof(setRMC)/sizeof(uint8_t), 100); HAL_Delay(100); // // Disable GLONASS mode // uint8_t disable_glonass[20] = {0xB5, 0x62, 0x06, 0x3E, 0x0C, 0x00, 0x00, 0x00, 0x20, 0x01, 0x06, 0x08, 0x0E, 0x00, 0x00, 0x00, 0x01, 0x01, 0x8F, 0xB2}; // HAL_UART_Transmit(uart_gethandle(), disable_glonass, sizeof(disable_glonass)/sizeof(uint8_t), 100); // HAL_Delay(100); // // // Enable power saving // uint8_t enable_powersave[10] = {0xB5, 0x62, 0x06, 0x11, 0x02, 0x00, 0x08, 0x01, 0x22, 0x92}; // HAL_UART_Transmit(uart_gethandle(), enable_powersave, sizeof(enable_powersave)/sizeof(uint8_t), 100); // HAL_Delay(100); // // // // Set dynamic model 6 (<1g airborne platform) // uint8_t airborne_model[] = { 0xB5, 0x62, 0x06, 0x24, 0x24, 0x00, 0xFF, 0xFF, 0x06, 0x03, 0x00, 0x00, 0x00, 0x00, 0x10, 0x27, 0x00, 0x00, 0x05, 0x00, 0xFA, 0x00, 0xFA, 0x00, 0x64, 0x00, 0x2C, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x16, 0xDC }; // HAL_UART_Transmit(uart_gethandle(), airborne_model, sizeof(airborne_model)/sizeof(uint8_t), 100); // HAL_Delay(100); // // // Begin DMA reception //HAL_UART_Receive_DMA(uart_gethandle(), nmeaBuffer, NMEABUFFER_SIZE); gpson = 1; } // Power off GPS module void gps_poweroff(void) { // NOTE: pchannel // position.hour = 0; // position.minute = 0; // position.second = 0; // position.altitude = 0; // position.latitude = 0; // position.longitude = 0; // position.day = 0; // position.month = 0; // position.fixtype = 0; // position.valid = 0; position.pdop = 0; position.sats_in_solution = 0; // position.speed = 0; uart_deinit(); HAL_GPIO_WritePin(GPS_NOTEN, 1); gpson = 0; } gps_data_t* gps_getdata(void) { return &position; } uint8_t gps_ison(void) { return gpson; } // vim:softtabstop=4 shiftwidth=4 expandtab