38 lines
751 B
C
38 lines
751 B
C
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#include "delay.h"
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#include "mk20dx128.h"
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// the systick interrupt is supposed to increment this at 1 kHz rate
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volatile uint32_t systick_millis_count = 0;
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void yield(void) {};
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uint32_t micros(void)
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{
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uint32_t count, current, istatus;
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__disable_irq();
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current = SYST_CVR;
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count = systick_millis_count;
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istatus = SCB_ICSR; // bit 26 indicates if systick exception pending
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__enable_irq();
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if ((istatus & SCB_ICSR_PENDSTSET) && current > ((F_CPU / 1000) - 50)) count++;
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current = ((F_CPU / 1000) - 1) - current;
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return count * 1000 + current / (F_CPU / 1000000);
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}
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void delay(uint32_t ms)
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{
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uint32_t start = micros();
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while (1) {
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if ((micros() - start) >= 1000) {
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ms--;
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if (ms == 0) break;
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start += 1000;
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}
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yield();
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}
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}
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