cmt/build/demo.stm32f0xx.c

#include "stm32f030.h"

/****** project hardware ******/
// on this demo board, there is a push button on PB13 and
// an LED on PA4 and PF5

#define LED  0x10 // port A bit 4  these LED are LOW=lit-up
#define LED2 0x50020 // port F bit 5
GPIO_TypeDef * GROUP[] = {GPIOA, GPIOB, GPIOC, GPIOD, 0, GPIOF};  // 0,0x10000,0x20000, etc
void gpio_set(uint32 bitPosition, bool value) {
  vu32* group = &((GROUP[bitPosition >> 16])->ODR);
  bitPosition &= 0xFFFF;
  if (value)
    *group |= bitPosition;
  else
    *group &= ~bitPosition;
}


/***** declarations ****/
#define NUM_EVENTS 10
volatile uint8 events[NUM_EVENTS];

void newEvent(uint8 e);
void ledTask(uint8 evt);
void respondToButtonTask(uint8 evt);

enum { EVT_NONE,
      EVT_TICK,
      EVT_BUTTON};

/********** interrupts **************/
volatile uint32 tick;	// increasing at 100 ticks/sec
			            // takes a year to roll-over

void timer_isr(void) {
  tick++;
  newEvent(EVT_TICK);
  // this interrupt is auto-ack'd
}

void button_isr(void) {
  newEvent(EVT_BUTTON);
  EXTI->PR |= 0x3001;    // ack it 
}

/** newEvent
 * add the event to the event queue
 * wrapped in critical section
 * 
 * @param the event
 */
void newEvent(uint8 e) {
	static uint nextEvent;
	dint();	// critical section
	events[nextEvent++] = e;
	if (nextEvent==NUM_EVENTS)
		nextEvent = 0;
	eint();
}

/***** init ******/
/* called by newlib startup */
void _init(void) {
  // startup code

  // use default clocks
  // turn on all the GPIO's
  RCC->AHBENR  = 0x005e0014;
  // enable SysCfg
  RCC->APB2ENR = 0x00004801;


  // enable the two LEDs as outputs
  GPIOA->MODER = (GPIOA->MODER & 0xFFFFFCFF) | 0x00000100; // port A bit 4
  GPIOF->MODER = (GPIOF->MODER & 0xFFFFF3FF) | 0x00000400; // port F bit 5
  // and the push button as input + pulldown
  GPIOB->PUPDR = (GPIOB->PUPDR & 0xF3FFFFFF) | 0x08000000; // pulldown on 13

  // keep the clocking system simple: just use the 8MHz HSI everywhere
  SysTick->LOAD = 10000;		// 10 msec
  SysTick->VAL  = 0;
  SysTick->CTRL = 3;			// count at 1usec, use interrupts
 
  /* to configure an interrupt on the stm32f0xx,
    - enable the EXTI->IMR for the pin
    - set EXTI->RTSR for select rising edge
    - set the SYSCFG->EXTICRx pin to route it 
    - enable the gating bit in the NVIC register 
    - don't forget to ack each interrupt at EXTI->PR
  */
  EXTI->IMR         = 0x2000;        // enable interrupt from line 13
  EXTI->RTSR        = 0x2000;        // interrupt on rising edge
  SYSCFG->EXTICR[3] = 0x0010;   // select prot B for exti-13
  NVIC->ISER[0]     = 0x00E1;        // enable in NVIC: gpio & watchdog

  gpio_set(LED,1); // TODO:
  gpio_set(LED2,1);
}


void main(void) {

	eint();

	while(1) {
		uint j;
		for (j=0; j<NUM_EVENTS; j++) {
			while (events[j]==EVT_NONE)
              {}
            ledTask(events[j]);
            respondToButtonTask(events[j]);
			events[j] = EVT_NONE;
		}
	}
}

/*********** task code, with states ************/
enum {LED_ON, LED_OFF};
enum {RTB_IDLE, RTB_ON};    // states
static uint8 rtbState           = RTB_IDLE;
static uint16 rtbTimerCount     = 0;
const uint16 BUTTON_LED_ON_TIME = 150;

void respondToButtonTask(uint8 evt) {
  switch(rtbState) {
    case RTB_IDLE:
      if (evt == EVT_BUTTON) {
        rtbState      = RTB_ON;
        rtbTimerCount = BUTTON_LED_ON_TIME;
        gpio_set(LED, LED_ON);
      }
      break;
    case RTB_ON:
      if (evt == EVT_TICK) {
        if (--rtbTimerCount == 0) {
          gpio_set(LED, LED_OFF);
          rtbState = RTB_IDLE;
        }
      }
      break;
    }
}

const int LED_ON_TIME  = 150;
const int LED_OFF_TIME = 50;
static uint8  ledState      = LED_OFF;
static uint16 ledTimerCount = 0;

void ledTask(uint8 evt) {
  switch(ledState) {
    case LED_OFF:
      if (evt == EVT_TICK) {
        if (++ledTimerCount > LED_OFF_TIME) {
          gpio_set(LED2, LED_ON);
          ledTimerCount = LED_ON_TIME;
          ledState      = LED_ON;
        }
      }
      break;
    case LED_ON:
      if (evt == EVT_TICK) {
        if (--ledTimerCount == 0) {
          gpio_set(LED2, LED_OFF);
          ledTimerCount = 0;
          ledState      = LED_OFF;
        }
      }
      break;
    }
}




/* vector table */
#define STACK_TOP 0x20002000
void default_isr(void) {}
extern void _start(void);

void (*myvectors[])(void) __attribute__ ((section(".vectors")))= {
	(void(*)(void)) STACK_TOP,     // stack pointer
	_start,        // code entry point
	default_isr,   // handle non-maskable interrupts
	default_isr, // handle hard faults
	0,0,0,0,                /* 10...1f */
	0,0,0,0,                /* 20...2f */
	0,0,0,timer_isr,        /* 30...3f */
	0,0,0,0,
	0,button_isr,button_isr,button_isr, /* 50...5f */
	0,0,0,0,                /* 60...6f */
	0,0,0,0,                /* 70...7f */
	0,0,0,0,                /* 80...8f */
	0,0,0,0,                /* 90...9f */
	0,0,0,0,                /* a0...af */
	0,0,0,0,                /* b0...bf */
	0,0,0,0,                /* c0...cf */
	0,0,0,0,                /* d0...df */
    0,0,0,0,  	            /* e0...ef */
	0,0,0,0,                /* f0...ff */
	0,0,0,0,				/* 100.10f */
	0,0,0,0                 /* 110.11f */
};