59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
#include "delay.h"
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/** \file
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\brief Delay routines
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*/
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#include "watchdog.h"
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/// delay microseconds
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/// \param delay time to wait in microseconds
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void delay(uint32_t delay) {
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wd_reset();
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while (delay > 65535) {
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delayMicrosecondsInterruptible(65533);
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delay -= 65535;
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wd_reset();
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}
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delayMicrosecondsInterruptible(delay & 0xFFFF);
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wd_reset();
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}
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/// delay milliseconds
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/// \param delay time to wait in milliseconds
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void delay_ms(uint32_t delay) {
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wd_reset();
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while (delay > 65) {
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delayMicrosecondsInterruptible(64999);
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delay -= 65;
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wd_reset();
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}
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delayMicrosecondsInterruptible(delay * 1000);
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wd_reset();
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}
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/// internal- wait for up to 65.5ms using a busy loop
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/// \param us time to wait in microseconds
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void delayMicrosecondsInterruptible(uint16_t us)
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{
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// for a one-microsecond delay, simply return. the overhead
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// of the function call yields a delay of approximately 1 1/8 us.
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if (--us == 0)
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return;
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// the following loop takes a quarter of a microsecond (4 cycles)
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// per iteration, so execute it four times for each microsecond of
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// delay requested.
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us <<= 2;
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// account for the time taken in the preceeding commands.
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us -= 2;
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// busy wait
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__asm__ __volatile__ ("1: sbiw %0,1" "\n\t" // 2 cycles
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"brne 1b" :
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"=w" (us) :
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"0" (us) // 2 cycles
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);
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}
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