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- #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 */
- };
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