You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
118 lines
3.1 KiB
C
118 lines
3.1 KiB
C
/*
|
|
* My first project
|
|
*
|
|
* It blinks LEDs like counting in binary, when the button is pressed, it reverses the order
|
|
*
|
|
* Build on top of libopenocm3, blackbox parts of code (setup()) copied from
|
|
* libopencm3-examples/examples/stm32/f1/stm32vl-discovery/button project
|
|
*
|
|
* Open source licence, let's say Artistic Licence, although it doesn't matter, as it is local only
|
|
*/
|
|
|
|
#include <libopencm3/stm32/rcc.h>
|
|
#include <libopencm3/stm32/gpio.h>
|
|
#include <libopencm3/stm32/f1/exti.h>
|
|
#include <libopencm3/stm32/f1/nvic.h>
|
|
#include <libopencm3/stm32/f1/timer.h>
|
|
#include <stdbool.h>
|
|
|
|
//#define DELAY 8000000 // Should be a second, or maybe not (second iff 8MHz clk, 1/3second if 24MHz clk) // Too long!!
|
|
#define STM32F1 1 // Needed for libopencm3
|
|
|
|
void setup_system (void) {
|
|
// Set up clock
|
|
rcc_clock_setup_in_hse_8mhz_out_24mhz();
|
|
}
|
|
|
|
void setup_gpio_out (void) {
|
|
// Enable clock for GPIO C
|
|
rcc_periph_clock_enable(RCC_GPIOC);
|
|
// GPIO C8 amd C9 are the two LEDs
|
|
gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO8 | GPIO9);
|
|
|
|
}
|
|
|
|
void setup_exti0_in (void) {
|
|
// Enable clock for GPIO A
|
|
rcc_periph_clock_enable(RCC_GPIOA);
|
|
|
|
// Enable AFIO (we need that to map GPIO to EXTI)
|
|
rcc_periph_clock_enable(RCC_AFIO);
|
|
|
|
// Enable EXTI0 interrupt.
|
|
// The interrupts are a bit magic, as the Internet says (the datasheet for F100RBT6B does not mention the EXTI/NVIC interface)
|
|
// This one is for EXTI0 ~~ GPIOx0 pins
|
|
nvic_enable_irq(NVIC_EXTI0_IRQ);
|
|
|
|
|
|
// GPIO A0 is the push button
|
|
// And we set it as a regular button and enable its interrupts in the next block
|
|
gpio_set_mode(GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO0);
|
|
|
|
// Configure the EXTI0 interrupts
|
|
// 1. Which pin
|
|
exti_select_source(EXTI0, GPIOA);
|
|
// 2. Which edge
|
|
exti_set_trigger(EXTI0, EXTI_TRIGGER_RISING);
|
|
// 3. Enable the interrupts
|
|
exti_enable_request(EXTI0);
|
|
}
|
|
|
|
void setup_tim6_periodic_irq (void) {
|
|
// Enable clock
|
|
rcc_periph_clock_enable(RCC_TIM6);
|
|
|
|
// Config:
|
|
// Set prescaler
|
|
timer_set_prescaler(TIM6, 65535);
|
|
// Set counter value
|
|
timer_set_period(TIM6, 183);
|
|
|
|
// Enable interrupts in NVIC
|
|
nvic_enable_irq(NVIC_TIM6_IRQ);
|
|
// Enable sending interrupts from the timer
|
|
timer_enable_irq(TIM6, TIM_DIER_UIE);
|
|
|
|
// Finally, enable the counter
|
|
timer_enable_counter(TIM6);
|
|
}
|
|
|
|
void setup (void) {
|
|
setup_system();
|
|
setup_gpio_out();
|
|
setup_exti0_in();
|
|
setup_tim6_periodic_irq();
|
|
}
|
|
|
|
// libopencm3 has a pre-declared interrupt handlers, so it needs to have this name
|
|
void exti0_isr (void) {
|
|
// Clear the interrupt
|
|
exti_reset_request(EXTI0);
|
|
// NB: For some reason it is at the begining in the examples
|
|
// It needs to be here (possibly because of reordering, when this was at the end, I usually got the interrupt twice).
|
|
|
|
// Toggle TIM6 in order to disable blinking
|
|
// Code inspired by libopencm3 source, since we cannot read the status otherwise…
|
|
TIM_CR1(TIM6) ^= TIM_CR1_CEN;
|
|
}
|
|
|
|
void tim6_isr (void) {
|
|
timer_clear_flag(TIM6, TIM_SR_UIF);
|
|
// Just change value of GPIO C9 (green LED)
|
|
uint16_t cur = gpio_get(GPIOC, GPIO9);
|
|
if (cur) {
|
|
gpio_clear(GPIOC, GPIO9);
|
|
} else {
|
|
gpio_set(GPIOC, GPIO9);
|
|
}
|
|
}
|
|
|
|
|
|
int main (void) {
|
|
setup();
|
|
|
|
while (true) __asm ("wfi");
|
|
return 0;
|
|
}
|
|
|