35 lines
1.2 KiB
C
35 lines
1.2 KiB
C
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#pragma once
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#include "derivative.h"
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#include <stdbool.h>
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extern volatile uint32_t ms_ticks;
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static inline void spin(volatile uint32_t count) {
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if (count == 0) return;
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while (count--) asm("nop");
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}
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static inline void systick_init(uint32_t ticks) {
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if ((ticks - 1) > 0xffffff) return; // Systick timer is 24 bit
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SysTick->LOAD = ticks - 1;
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SysTick->VAL = 0;
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SysTick->CTRL = SysTick_CTRL_ENABLE_Msk // Enable systick timer
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| SysTick_CTRL_TICKINT_Msk // Enable interrupt
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| SysTick_CTRL_CLKSOURCE_Msk; // Use butin-in clock
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}
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// t: expiration time, prd: period
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static inline bool timer_expired(uint32_t *t, uint32_t prd) {
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if (ms_ticks + prd < *t) *t = 0; // Time wrapped? Reset timer
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if (*t == 0) *t = ms_ticks + prd; // First poll? Set expiration
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if (*t > ms_ticks) return false; // Not expired yet, return
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*t = (ms_ticks - *t) > prd ? ms_ticks + prd : *t + prd; // Next expiration time
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return true; // Expired, return true
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}
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static inline void delay_ms(uint32_t ms) {
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uint32_t start = ms_ticks;
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while (ms_ticks - start < ms) asm("nop");
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}
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