@@ -405,166 +405,173 @@ void display_process(therm_settings_t* s
status->state = STATE_IDLE;
}
else {
user_input(&set->setpoint_brew);
// Event Handler
if(status->temp >= status->setpoint) {
status->state = STATE_MAINTAIN_BREW;
} break;
case STATE_MAINTAIN_BREW:
{
// Write text to OLED
// [ therm : ready to brew ]
// [ 30 => 120 C ]
ssd1306_DrawString("Preheated!", 0, 0);
//ssd1306_drawlogo();
draw_setpoint(status);
status->pid_enabled = 1;
status->setpoint = set->setpoint_brew;
// Button handler
if(SW_BTN_PRESSED) {
save_setpoints(); // TODO: Check for mod
// N/A
case STATE_PREHEAT_STEAM:
// [ therm : preheating steam ]
ssd1306_DrawString("Preheating...", 0, 0);
status->setpoint = set->setpoint_steam;
user_input(&set->setpoint_steam);
status->state = STATE_MAINTAIN_STEAM;
case STATE_MAINTAIN_STEAM:
// [ therm : ready to steam ]
ssd1306_DrawString("Ready to Steam!", 0, 0);
case STATE_TC_ERROR:
ssd1306_DrawString("Error:", 0, 0);
ssd1306_DrawString("Connect thermocouple", 1, 0);
if(status->tc_errno == 1)
ssd1306_DrawString("#1, Check Sensor", 1, 0);
else if(status->tc_errno == 4)
ssd1306_DrawString("#4, Check Sensor", 1, 0);
else
ssd1306_DrawString("#?, Unknown Error", 1, 0);
ssd1306_DrawString("Press -> to ignore", 3, 0);
else if(SW_RIGHT_PRESSED) {
set->ignore_tc_error = 1;
// Maybe handle if TC is plugged in
// Something is terribly wrong
default:
status->pid_enabled = 0;
if(last_state != status->state) {
// Clear screen on state change
goto_mode = 2;
trigger_drawsetpoint = 1;
ssd1306_clearscreen();
// 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;
int32_t temp_last = 43002;
int32_t setpoint_last = 10023;
void draw_setpoint(therm_status_t* status) {
// FIXME: need to do this when switching modes too
if(status->temp != temp_last || trigger_drawsetpoint) {
char tempstr[3];
itoa_fp(status->temp, status->temp_frac, tempstr);
ssd1306_DrawStringBig(" ", 3, 0);
ssd1306_DrawStringBig(tempstr, 3, 0);
if(trigger_drawsetpoint)
ssd1306_DrawStringBig(">", 3, 74);
if(status->setpoint != setpoint_last || trigger_drawsetpoint) {
itoa(status->setpoint, tempstr, 10);
ssd1306_DrawStringBig(" ", 3, 90);
ssd1306_DrawStringBig(tempstr, 3, 90);
trigger_drawsetpoint = 0;
setpoint_last = status->setpoint;
temp_last = status->temp;
// vim:softtabstop=4 shiftwidth=4 expandtab
@@ -69,199 +69,201 @@ int main(void)
ssd1306_Init();
// Default settings
set.boottobrew = 0;
set.temp_units = TEMP_UNITS_CELSIUS;
set.windup_guard = 1;
set.k_p = 1;
set.k_i = 1;
set.k_d = 1;
set.ignore_tc_error = 0;
set.setpoint_brew = 0;
set.setpoint_steam = 0;
// Default status
status.temp = 0;
status.temp_frac = 0;
status.state_resume = 0;
status.state = STATE_IDLE;
status.setpoint = 0;
status.pid_enabled = 0;
// Load settings (if any) from EEPROM
restore_settings();
if(set.boottobrew)
status.state = STATE_PREHEAT_BREW; // Go to brew instead of idle if configured thusly
// Startup screen
ssd1306_DrawString("therm v0.1", 1, 40);
ssd1306_DrawString("protofusion.org/therm", 3, 0);
HAL_Delay(1500);
// Main loop
while(1)
// Process sensor inputs
process();
// Run state machine
display_process(&set, &status);
/** System Clock Configuration
*/
void SystemClock_Config(void)
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_PeriphCLKInitTypeDef PeriphClkInit;
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48;
RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI48;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1);
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_HSI48;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
__SYSCFG_CLK_ENABLE();
void update_temp() {
// Assert CS
HAL_GPIO_WritePin(MAX_CS, 0);
uint8_t rxdatah[1] = {0x00};
uint8_t rxdatal[1] = {0x00};
HAL_SPI_Receive(&hspi1, rxdatah, 1, 100);
HAL_SPI_Receive(&hspi1, rxdatal, 1, 100);
// Release CS
HAL_GPIO_WritePin(MAX_CS, 1);
// Assemble data array into one var
uint16_t temp_pre = rxdatal[0] | (rxdatah[0]<<8);
if(temp_pre & 0b0000000000000010) {
//ssd1306_DrawString("Fatal Error", 3, 35);
HAL_Delay(100);
HAL_Delay(100); // FIXME: remove?
status.tc_errno = 4;
status.state = STATE_TC_ERROR;
else if(temp_pre & 0b0000000000000001 && !set.ignore_tc_error) {
status.tc_errno = 1;
status.state_resume = status.state;
if(status.state == STATE_TC_ERROR)
status.state = status.state_resume;
uint8_t sign = status.temp >> 15;// top bit is sign
temp_pre = temp_pre >> 2; // Drop 2 lowest bits
status.temp_frac = temp_pre & 0b11; // get fractional part
status.temp_frac *= 25; // each bit is .25 a degree, up to fixed point
temp_pre = temp_pre >> 2; // Drop 2 fractional bits
int8_t signint;
if(sign) {
signint = -1;
signint = 1;
// Convert to Fahrenheit
if(set.temp_units == TEMP_UNITS_FAHRENHEIT)
status.temp = signint * ((temp_pre*100) + status.temp_frac);
status.temp = status.temp * 1.8;
status.temp += 3200;
status.temp_frac = status.temp % 100;
status.temp /= 100;
status.temp += set.temp_offset;
// Use Celsius values
status.temp = temp_pre * signint;
// PID implementation
// TODO: Make struct that has the last_temp and i_state in it, pass by ref. Make struct that has other input values maybe.
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 = set.windup_guard / 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 * (status.temp - last_pid_temp));
// Save temperature for next iteration
last_pid_temp = status.temp;
last_pid_temp_frac = status.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;
#ifndef STATES_H
#define STATES_H
typedef struct {
int32_t temp;
uint8_t temp_frac;
uint8_t state_resume;
uint8_t state;
int32_t setpoint;
uint8_t pid_enabled;
uint8_t tc_errno;
} therm_status_t;
uint8_t boottobrew;
uint8_t temp_units;
uint16_t windup_guard;
uint16_t k_p;
uint16_t k_i;
uint16_t k_d;
int16_t temp_offset;
uint8_t ignore_tc_error;
int16_t setpoint_brew;
int16_t setpoint_steam;
} therm_settings_t;
enum tempunits {
TEMP_UNITS_CELSIUS = 0,
TEMP_UNITS_FAHRENHEIT,
};
enum state {
STATE_IDLE = 0,
STATE_SETP,
STATE_SETI,
STATE_SETD,
STATE_SETSTEPS,
STATE_SETWINDUP,
STATE_SETBOOTTOBREW,
STATE_SETUNITS,
STATE_SETTEMPOFFSET,
STATE_PREHEAT_BREW,
STATE_MAINTAIN_BREW,
STATE_PREHEAT_STEAM,
STATE_MAINTAIN_STEAM,
STATE_TC_ERROR
#endif
Status change: