#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;
// ISR ticks var TODO: Double check functionality after volatilazation... needed on ARM?
volatile uint32_t ticks = 0;
// Increase on each press, and increase at a fast rate after duration elapsed of continuously holding down... somehow...
uint32_t change_time_reset = 0;
#define CHANGE_PERIOD_MS 100
#define CHANGE_ELAPSED (ticks - change_time_reset) > CHANGE_PERIOD_MS
#define CHANGE_RESET change_time_reset = ticks
int16_t setpoint_brew = 0;
int16_t setpoint_steam = 0;
// 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,
};
uint8_t state = STATE_IDLE;
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();
void save_setpoints();
int main(void)
{
// Init clocks
SystemInit();
// Init GPIO
init_gpio();
// Init USB
//Set_USBClock();
//USB_Interrupts_Config();
//USB_Init();
// Turn on power LED
@@ -170,97 +180,96 @@ 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;
else
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);
GPIO_SetBits(SSR_PIN);
last_ssr_on = ticks;
@@ -320,449 +329,436 @@ uint16_t k_d = 1;*/
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 save_setpoints()
DATA_EEPROM_ProgramWord(EEPROM_ADDR_BREWTEMP, setpoint_brew);
DATA_EEPROM_ProgramWord(EEPROM_ADDR_STEAMTEMP, setpoint_steam);
// TODO: Save/restore temperature setpoint settings
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);
setpoint_brew = (*(__IO uint32_t*)EEPROM_ADDR_BREWTEMP);
setpoint_steam = (*(__IO uint32_t*)EEPROM_ADDR_STEAMTEMP);
void user_input(uint16_t* to_modify)
if(CHANGE_ELAPSED) {
// TODO: Make function that takes reference to a var and increase/decreases it based on buttonpress
if(!GPIO_ReadInputDataBit(SW_UP) ) {
CHANGE_RESET;
(*to_modify)++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && (*to_modify) > 0) {
(*to_modify)--;
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;
itoa_fp(temp, temp_frac, tempstr);
ssd1306_DrawString("Temp: ", 3, 40);
ssd1306_DrawString(" ", 3, 72);
ssd1306_DrawString(tempstr, 3, 72);
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--;
else {
user_input(&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++;
user_input(&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--;
user_input(&k_d);
case STATE_SETWINDUP:
// [ therm :: set windup ]
// [ g = 12 ]
ssd1306_DrawString("Windup Guard", 0, 40);
itoa(windup_guard, tempstr);
ssd1306_DrawString("G=", 1, 45);
state = STATE_SETBOOTTOBREW;
windup_guard++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && windup_guard > 0) {
windup_guard--;
user_input(&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 = setpoint_brew;
save_setpoints(); // TODO: Check for mod
setpoint_brew++;
user_input(&setpoint_brew);
else if(!GPIO_ReadInputDataBit(SW_DOWN) && setpoint_brew > 0) {
setpoint_brew--;
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 ]
setpoint = setpoint_steam;
setpoint_steam++;
else if(!GPIO_ReadInputDataBit(SW_DOWN) && setpoint_steam > 0) {
setpoint_steam--;
user_input(&setpoint_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;
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;
// 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++;
Status change: