50 lines
1.1 KiB
C
50 lines
1.1 KiB
C
#include <libopencm3/cm3/systick.h>
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#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/stm32/rcc.h>
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/* Nucleo-G474RE: LD2 is on PA5 */
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#define BLINK_PORT GPIOA
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#define BLINK_PIN GPIO5
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#define BLINK_PERIOD_MS 1000
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static volatile uint32_t s_ticks = 0;
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void sys_tick_handler(void) { s_ticks++; }
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static void delay_ms(uint32_t ms) {
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uint32_t until = s_ticks + ms;
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while (s_ticks < until)
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;
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}
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static void clock_setup(void) {
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rcc_clock_setup_pll(&rcc_hsi_configs[RCC_CLOCK_3V3_170MHZ]);
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}
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static void systick_setup(void) {
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/* 1 ms tick at 170 MHz core clock */
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systick_set_reload(rcc_ahb_frequency / 1000 - 1);
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systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
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systick_counter_enable();
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systick_interrupt_enable();
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}
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static void gpio_setup(void) {
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rcc_periph_clock_enable(RCC_GPIOA);
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gpio_mode_setup(BLINK_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, BLINK_PIN);
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gpio_set_output_options(BLINK_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_LOW,
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BLINK_PIN);
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}
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int main(void) {
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clock_setup();
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systick_setup();
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gpio_setup();
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while (1) {
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gpio_toggle(BLINK_PORT, BLINK_PIN);
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delay_ms(BLINK_PERIOD_MS);
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}
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return 0;
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}
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