#include "main.h"
#include "stm32l100c_discovery.h"
#include "ssd1306.h"
#include "config.h"
// USB includes
#include "hw_config.h"
#include "usb_lib.h"
#include "usb_desc.h"
#include "usb_pwr.h"
#include "stringhelpers.h"
// TODO: Grab buttonpresses with interrupts
// TODO: Eliminate screen buffer since we aren't using it...
// USB Supporting Vars
extern __IO uint8_t Receive_Buffer[64];
extern __IO uint32_t Receive_length ;
extern __IO uint32_t length ;
uint8_t Send_Buffer[64];
uint32_t packet_sent=1;
uint32_t packet_receive=1;
// Globalish setting vars
uint8_t boottobrew = 0;
#define WINDUP_GUARD_GAIN 100
uint16_t windup_guard = WINDUP_GUARD_GAIN;
uint16_t k_p = 1;
uint16_t k_i = 1;
uint16_t k_d = 1;
// State definition
enum state {
STATE_IDLE = 0,
STATE_SETP,
STATE_SETI,
STATE_SETD,
STATE_SETWINDUP,
STATE_SETBOOTTOBREW,
STATE_PREHEAT_BREW,
STATE_MAINTAIN_BREW,
STATE_PREHEAT_STEAM,
STATE_MAINTAIN_STEAM,
};
static __IO uint32_t TimingDelay;
// Move to header file
void init_gpio();
void init_spi();
void process();
void machine();
void delay(__IO uint32_t nTime);
void restore_settings();
void save_settings();
int main(void)
{
// Init clocks
SystemInit();
// Init GPIO
init_gpio();
// Init USB
//Set_USBClock();
//USB_Interrupts_Config();
//USB_Init();
// Turn on power LED
GPIO_SetBits(LED_POWER);
// TODO: Awesome pwm of power LED (TIM4_CH4 or TIM11_CH1)
// TODO: PWM of stat led (TIM3_CH2)
// Configure 1ms SysTick (change if more temporal resolution needed)
RCC_ClocksTypeDef RCC_Clocks;
RCC_GetClocksFreq(&RCC_Clocks);
SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);
// Init SPI busses
init_spi();
// Init OLED over SPI
ssd1306_Init();
ssd1306_clearscreen();
// Startup screen
ssd1306_DrawString("therm v0.1", 1, 40);
ssd1306_DrawString("protofusion.org/therm", 3, 0);
delay(1500);
restore_settings();
GPIO_ResetBits(LED_STAT);
// Main loop
while(1)
// Process sensor inputs
process();
// Run state machine
machine();
}
// Read temperature and update global temp vars
int16_t temp = 0;
uint8_t temp_frac = 0;
void update_temp() {
// Assert CS
GPIO_ResetBits(MAX_CS);
delay(1);
// This may not clock at all... might need to send 16 bits first
SPI_I2S_SendData(SPI2, 0xAAAA); // send dummy data
//SPI_I2S_SendData(SPI2, 0xAA); // send dummy data
uint16_t temp_pre = SPI_I2S_ReceiveData(SPI2);
if(temp_pre & 0b0000000000000010) {
ssd1306_DrawString("Fatal Error", 2, 35);
else if(temp_pre & 0b0000000000000001) {
ssd1306_DrawString("Error: No TC", 2, 40);
temp = 0;
temp_frac = 0;
else
uint8_t sign = temp >> 15;// top bit is sign
temp_pre = temp_pre >> 2; // Drop 2 lowest bits
temp_frac = temp_pre & 0b11; // get fractional part
temp_frac *= 25; // each bit is .25 a degree, up to fixed point
temp_pre = temp_pre >> 2; // Drop 2 fractional bits
if(sign) {
temp = -temp_pre;
else {
temp = temp_pre;
// Deassert CS
GPIO_SetBits(MAX_CS);
// PID implementation
int16_t last_pid_temp = 0;
uint8_t last_pid_temp_frac = 0;
int16_t i_state = 0;
int16_t update_pid(uint16_t k_p, uint16_t k_i, uint16_t k_d, int16_t temp, uint8_t temp_frac, int16_t setpoint)
// Calculate instantaneous error
int16_t error = (int16_t)setpoint - (int16_t)temp; // TODO: Use fixed point fraction
// Proportional component
int16_t p_term = k_p * error;
// Error accumulator (integrator)
i_state += error;
// to prevent the iTerm getting huge despite lots of
// error, we use a "windup guard"
// (this happens when the machine is first turned on and
// it cant help be cold despite its best efforts)
// not necessary, but this makes windup guard values
// relative to the current iGain
int16_t windup_guard_res = WINDUP_GUARD_GAIN / k_i;
// Calculate integral term with windup guard
if (i_state > windup_guard_res)
i_state = windup_guard_res;
else if (i_state < -windup_guard_res)
i_state = -windup_guard_res;
int16_t i_term = k_i * i_state;
// Calculate differential term (slope since last iteration)
int16_t d_term = (k_d * (temp - last_pid_temp));
// Save temperature for next iteration
last_pid_temp = temp;
last_pid_temp_frac = temp_frac;
int16_t result = p_term + i_term - d_term;
// Put out tenths of percent, 0-1000.
if(result > 1000)
result = 1000;
else if(result < -1000)
result = -1000;
// Return feedback
return result;
uint32_t ticks = 0;
uint32_t last_ssr_on = 0;
uint32_t last_led = 0;
int32_t setpoint = 0;
int16_t ssr_output = 0; // Duty cycle of ssr, 0 to SSR_PERIOD
uint8_t pid_enabled = 0;
// Process things
void process()
update_temp(); // Read MAX31855
// TODO: Add calibration offset (linear)
if(ticks - last_led > 400)
GPIO_ToggleBits(LED_POWER);
last_led = ticks;
// Every 200ms, set the SSR on unless output is 0
if((ticks - last_ssr_on > SSR_PERIOD))
if(pid_enabled)
// Get ssr output for next time
int16_t power_percent = update_pid(k_p, k_i, k_d, temp, temp_frac, setpoint);
//power-percent is 0-1000
ssr_output = power_percent; //(((uint32_t)SSR_PERIOD * (uint32_t)10 * (uint32_t)100) * power_percent) / (uint32_t)1000000;
ssr_output = 0;
// Only support heating (ssr_output > 0) right now
if(ssr_output > 0) {
char tempstr[6];
itoa(ssr_output, tempstr);
ssd1306_DrawString("#=", 2, 45);
ssd1306_DrawString(" ", 2, 57);
ssd1306_DrawString(tempstr, 2, 57);
GPIO_SetBits(LED_STAT);
last_ssr_on = ticks;
// Kill SSR after elapsed period less than SSR_PERIOD
if(ticks - last_ssr_on > ssr_output)
void draw_setpoint() {
char tempstr[3];
itoa_fp(temp, temp_frac, tempstr);
//ssd1306_DrawString(" ", 3, 40);
ssd1306_DrawString(tempstr, 3, 40);
ssd1306_DrawString("-> ", 3, 80);
itoa(setpoint, tempstr);
ssd1306_DrawString(" ", 3, 95);
ssd1306_DrawString(tempstr, 3, 95);
uint8_t state = STATE_IDLE;
uint8_t goto_mode = 2;
// State machine
uint8_t sw_btn_last = 0;
uint8_t sw_up_last = 0;
uint8_t sw_down_last = 0;
uint8_t sw_left_last = 0;
uint8_t sw_right_last = 0;
#define SW_BTN_PRESSED (sw_btn_last == 0 && sw_btn == 1) // rising edge on buttonpress
#define SW_UP_PRESSED (sw_up_last == 0 && sw_up == 1)
#define SW_DOWN_PRESSED (sw_down_last == 0 && sw_down == 1)
#define SW_LEFT_PRESSED (sw_left_last == 0 && sw_left == 1)
#define SW_RIGHT_PRESSED (sw_right_last == 0 && sw_right == 1)
/*
* uint8_t boottobrew = 0;
uint16_t k_d = 1;*/
#define EEPROM_ADDR_WINDUP_GUARD 0x0808001C
#define EEPROM_ADDR_BOOTTOBREW 0x08080020
#define EEPROM_ADDR_K_P 0x8080024
#define EEPROM_ADDR_K_I 0x8080028
#define EEPROM_ADDR_K_D 0x808002C
void save_settings()
DATA_EEPROM_Unlock();
// Try programming a word at an address divisible by 4
DATA_EEPROM_ProgramWord(EEPROM_ADDR_BOOTTOBREW, boottobrew);
DATA_EEPROM_ProgramWord(EEPROM_ADDR_WINDUP_GUARD, windup_guard);
DATA_EEPROM_ProgramWord(EEPROM_ADDR_K_P, k_p);
DATA_EEPROM_ProgramWord(EEPROM_ADDR_K_I, k_i);
DATA_EEPROM_ProgramWord(EEPROM_ADDR_K_D, k_d);
DATA_EEPROM_Lock();
void restore_settings()
while(FLASH_GetStatus()==FLASH_BUSY);
boottobrew = (*(__IO uint32_t*)EEPROM_ADDR_BOOTTOBREW);
windup_guard = (*(__IO uint32_t*)EEPROM_ADDR_WINDUP_GUARD);
k_p = (*(__IO uint32_t*)EEPROM_ADDR_K_P);
k_i = (*(__IO uint32_t*)EEPROM_ADDR_K_I);
k_d = (*(__IO uint32_t*)EEPROM_ADDR_K_D);
itoa(windup_guard, tempstr);
ssd1306_DrawString("Read: ", 3, 40);
ssd1306_DrawString(" ", 3, 72);
ssd1306_DrawString(tempstr, 3, 72);
void machine()
uint8_t last_state = state;
uint8_t sw_btn = !GPIO_ReadInputDataBit(SW_BTN);
uint8_t sw_up = !GPIO_ReadInputDataBit(SW_UP);
uint8_t sw_down = !GPIO_ReadInputDataBit(SW_DOWN);
uint8_t sw_left = !GPIO_ReadInputDataBit(SW_LEFT);
uint8_t sw_right = !GPIO_ReadInputDataBit(SW_RIGHT);
switch(state)
// Idle state
case STATE_IDLE:
// Write text to OLED
// [ therm :: idle ]
ssd1306_DrawString("therm :: idle ", 0, 40);
pid_enabled = 0;
ssd1306_DrawString("Temp: ", 3, 40);
ssd1306_drawlogo();
switch(goto_mode) {
case 2:
ssd1306_DrawString("-> brew ", 1, 40);
} break;
case 1:
ssd1306_DrawString("-> setup ", 1, 40);
case 0:
ssd1306_DrawString("-> reset ", 1, 40);
// Button handler
if(SW_BTN_PRESSED) {
state = STATE_PREHEAT_BREW;
break;
state = STATE_SETP;
state = STATE_IDLE;
default:
else if(SW_UP_PRESSED && goto_mode < 2) {
goto_mode++;
else if(SW_DOWN_PRESSED && k_p > 0 && goto_mode > 0) {
goto_mode--;
// Event Handler
// N/A
case STATE_SETP:
// [ therm :: set p ]
// [ p = 12 ]
ssd1306_DrawString("Proportional", 0, 40);
itoa(k_p, tempstr);
ssd1306_DrawString("P=", 1, 45);
ssd1306_DrawString(" ", 1, 57);
ssd1306_DrawString(tempstr, 1, 57);
ssd1306_DrawString("Press to accept", 3, 40);
state = STATE_SETI;
else if(!GPIO_ReadInputDataBit(SW_UP)) {
k_p++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && k_p > 0) {
k_p--;
case STATE_SETI:
// [ therm :: set i ]
// [ i = 12 ]
ssd1306_DrawString("Integral", 0, 40);
itoa(k_i, tempstr);
ssd1306_DrawString("I=", 1, 45);
state = STATE_SETD;
k_i++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && k_i > 0) {
k_i--;
case STATE_SETD:
// [ therm :: set d ]
// [ d = 12 ]
ssd1306_DrawString("Derivative", 0, 40);
itoa(k_d, tempstr);
ssd1306_DrawString("D=", 1, 45);
state = STATE_SETWINDUP;
k_d++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && k_d > 0) {
k_d--;
case STATE_SETWINDUP:
// [ therm :: set windup ]
// [ g = 12 ]
ssd1306_DrawString("Windup Guard", 0, 40);
ssd1306_DrawString("G=", 1, 45);
state = STATE_SETBOOTTOBREW;
windup_guard++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && windup_guard > 0) {
windup_guard--;
case STATE_SETBOOTTOBREW:
ssd1306_DrawString("Boot to Brew", 0, 40);
ssd1306_DrawString("btb=", 1, 45);
if(boottobrew)
ssd1306_DrawString("Enabled ", 1, 70);
ssd1306_DrawString("Disabled", 1, 70);
save_settings();
boottobrew = 1;
else if(!GPIO_ReadInputDataBit(SW_DOWN)) {
boottobrew = 0;
case STATE_PREHEAT_BREW:
// [ therm : preheating brew ]
// [ 30 => 120 C ]
ssd1306_DrawString("Preheating...", 0, 40);
draw_setpoint();
pid_enabled = 1;
setpoint++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && setpoint > 0) {
setpoint--;
if(temp >= setpoint) {
state = STATE_MAINTAIN_BREW;
case STATE_MAINTAIN_BREW:
// [ therm : ready to brew ]
ssd1306_DrawString("Ready to Brew!", 0, 40);
case STATE_PREHEAT_STEAM:
// [ therm : preheating steam ]
state = STATE_MAINTAIN_STEAM;
case STATE_MAINTAIN_STEAM:
// [ therm : ready to steam ]
ssd1306_DrawString("Ready to Steam!", 0, 40);
// Something is terribly wrong
if(last_state != state) {
// Clear screen on state change
goto_mode = 2;
// Last buttonpress
sw_btn_last = sw_btn;
sw_up_last = sw_up;
sw_down_last = sw_down;
sw_left_last = sw_left;
sw_right_last = sw_right;
// Delay a number of systicks
void delay(__IO uint32_t nTime)
TimingDelay = nTime;
while(TimingDelay != 0);
// ISR-triggered decrement of delay and increment of tickcounter
void TimingDelay_Decrement(void)
if (TimingDelay != 0x00)
TimingDelay--;
ticks++;
void init_spi(void)
SPI_InitTypeDef SPI_InitStructure;
// OLED IC
SPI_Cmd(SPI1, DISABLE);
SPI_InitStructure.SPI_Direction = SPI_Direction_1Line_Tx;
SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStructure.SPI_CRCPolynomial = 7;
SPI_Init(SPI1, &SPI_InitStructure);
SPI_Cmd(SPI1, ENABLE); /* Enable the SPI */
// MAX IC
SPI_Cmd(SPI2, DISABLE);
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b; // Andysworkshop
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low; // From andysworkshop
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; // same
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8;
SPI_Init(SPI2, &SPI_InitStructure);
SPI_Cmd(SPI2, ENABLE); /* Enable the SPI */
void init_gpio(void) {
GPIO_InitTypeDef GPIO_InitStruct;
// Enable SPI clocks
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);
// Enable GPIO clocks
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC|RCC_AHBPeriph_GPIOB|RCC_AHBPeriph_GPIOA, ENABLE);
// Enable DMA clocks (Is AHB even the right thing???)
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); // EMZ TODO get the right ones
/*Configure GPIO pin : PC */
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_400KHz;
GPIO_Init(GPIOC, &GPIO_InitStruct);
/*Configure GPIO pin : PB */
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_10|GPIO_Pin_12
|GPIO_Pin_9;
GPIO_Init(GPIOB, &GPIO_InitStruct);
/*Configure GPIO pin : PA */
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_15;
GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6
|GPIO_Pin_7;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
/** SPI1 GPIO Configuration
PA5 ------> SPI1_SCK
PA7 ------> SPI1_MOSI
*/
/*Enable or disable the AHB peripheral clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/*Configure GPIO pin : PA: MOSI,SCK */
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5|GPIO_Pin_7;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_10MHz;
/*Configure GPIO pin alternate function */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
/** SPI2 GPIO Configuration
PB13 ------> SPI2_SCK
PB14 ------> SPI2_MISO
PB15 ------> SPI2_MOSI
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
// SPI PINSSS
/*Configure GPIO pin : PB, MOSI, SCK */
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13|GPIO_Pin_15;
GPIO_InitTypeDef GPIO_InitStruct2;
// MISO
GPIO_InitStruct2.GPIO_Pin = GPIO_Pin_14;
GPIO_InitStruct2.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct2.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStruct2.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_Init(GPIOB, &GPIO_InitStruct2);
//Configure GPIO pin alternate function
GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_SPI2);
/** USB GPIO Configuration
PA11 ------> USB_DM
PA12 ------> USB_DP
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_11|GPIO_Pin_12;
// vim:softtabstop=4 shiftwidth=4 expandtab
Status change: