116 lines
2.3 KiB
C

#include <stdint.h>
#include <stm32f4xx.h>
#include <stdbool.h>
volatile uint32_t ISR_Ticks = 0;
struct TASK {
void (*fn)(void);
uint32_t counter;
uint32_t counter_rst;
};
uint8_t Tasks_len = 0;
struct TASK Tasks[8];
void SysTick_Handler()
{
ISR_Ticks++;
}
bool addTask(void (*fn)(void), uint32_t counter, uint32_t counter_init)
{
if (Tasks_len >= 8) {
return false;
}
Tasks[Tasks_len].fn = fn;
Tasks[Tasks_len].counter = counter_init;
Tasks[Tasks_len].counter_rst = counter;
Tasks_len++;
return true;
}
void taskGreen()
{
GPIOD->ODR ^= GPIO_ODR_OD12;
}
void taskOrange()
{
GPIOD->ODR ^= GPIO_ODR_OD13;
}
void taskRed()
{
GPIOD->ODR ^= GPIO_ODR_OD14;
}
void taskBlue()
{
GPIOD->ODR ^= GPIO_ODR_OD15;
}
enum STATE {
STATE_GREEN,
STATE_ORANGE,
STATE_RED
};
int main(void)
{
// GPIO Port D Clock Enable
RCC->AHB1ENR = RCC_AHB1ENR_GPIODEN;
// GPIO Port D Pin 15 down to 12 Push/Pull Output
GPIOD->MODER = GPIO_MODER_MODER12_0
| GPIO_MODER_MODER13_0
| GPIO_MODER_MODER14_0
| GPIO_MODER_MODER15_0;
// Set all leds off
GPIOD->ODR = 0;
// SysTick enable with interupt and clk source to AHB/8
SysTick->CTRL = SysTick_CTRL_TICKINT_Msk | SysTick_CTRL_ENABLE_Msk;
SysTick->LOAD = 2000; // 1 ms / (16 MHz / 8)
addTask(*taskGreen, 200, 100);
addTask(*taskOrange, 500, 200);
addTask(*taskRed, 750, 300);
addTask(*taskBlue, 300, 400);
// Do forever:
while (1)
{
// Wait a moment
while (ISR_Ticks == 0)
{
__asm__(" WFI"); // sleep until SysTick
}
uint32_t ticks = ISR_Ticks;
ISR_Ticks = 0;
// decrement all counters
for (uint8_t i=0; i<Tasks_len; i++)
{
if (Tasks[i].counter > ticks)
{
Tasks[i].counter -= ticks;
}
else
{
Tasks[i].counter = 0;
}
}
// rust all tasks where the counter has run out
for (uint8_t i=0; i<Tasks_len; i++)
{
if (Tasks[i].counter == 0)
{
Tasks[i].fn();
Tasks[i].counter = Tasks[i].counter_rst;
}
}
}
}