@@ -34,24 +34,25 @@ enum state {
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);
int main(void)
{
// Init clocks
SystemInit();
// Init GPIO
init_gpio();
// Init USB
//Set_USBClock();
@@ -70,47 +71,47 @@ int main(void)
SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);
// Init SPI busses
init_spi();
// Init OLED over SPI
ssd1306_Init();
ssd1306_block_write();
// Startup screen
ssd1306_DrawString("therm v0.1", 1, 40);
ssd1306_DrawString("protofusion.org/therm", 3, 0);
Delay(1500);
delay(1500);
// 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);
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;
@@ -125,25 +126,25 @@ void update_temp() {
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);
uint32_t ticks = 0;
uint32_t last_ssr_on = 0;
uint32_t last_led = 0;
int32_t setpoint = 0;
uint16_t k_p = 1;
uint16_t k_i = 1;
uint16_t k_d = 1;
uint8_t ssr_output = 0; // Duty cycle of ssr, 0 to SSR_PERIOD
@@ -151,51 +152,48 @@ uint8_t ssr_output = 0; // Duty cycle of
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
if(ticks - last_ssr_on > SSR_PERIOD)
// Every 200ms, set the SSR on unless output is 0
if((ticks - last_ssr_on > SSR_PERIOD) && ssr_output > 0)
GPIO_SetBits(LED_STAT);
last_ssr_on = ticks;
// Kill SSR after elapsed period less than SSR_PERIOD
if(ticks - last_ssr_on > ssr_output || !ssr_output)
if(ticks - last_ssr_on > ssr_output)
GPIO_ResetBits(LED_STAT);
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
void machine()
uint8_t last_state = state;
switch(state)
// Idle state
@@ -356,121 +354,140 @@ void machine()
case STATE_PREHEAT_BREW:
// Write text to OLED
// [ therm : preheating brew ]
// [ 30 => 120 C ]
ssd1306_DrawString("Preheating...", 0, 40);
draw_setpoint();
// Button handler
if(!GPIO_ReadInputDataBit(SW_BTN)) {
state = STATE_IDLE;
else if(!GPIO_ReadInputDataBit(SW_UP)) {
setpoint++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && setpoint > 0) {
setpoint--;
// Event Handler
if(temp >= setpoint) {
state = STATE_MAINTAIN_BREW;
} break;
case STATE_MAINTAIN_BREW:
// [ therm : ready to brew ]
ssd1306_DrawString("Ready to Brew!", 0, 40);
// N/A
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
default:
if(last_state != state) {
// Clear screen on state change
/**
* @brief Inserts a delay time.
* @param nTime: specifies the delay time length, in 1 ms.
* @retval None
*/
void Delay(__IO uint32_t nTime)
// Delay a number of systicks
void delay(__IO uint32_t nTime)
TimingDelay = nTime;
while(TimingDelay != 0);
* @brief Decrements the TimingDelay variable.
* @param None
// ISR-triggered decrement of delay and increment of tickcounter
void TimingDelay_Decrement(void)
if (TimingDelay != 0x00)
TimingDelay--;
ticks++;
void init_spi(void)
Status change: