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/**
* @file delay.h
* @brief Delay implementation
*/
#ifndef _DELAY_H_
#define _DELAY_H_
/**
* @brief Delay the given number of microseconds.
*
* Note that this function currently assumes you are on a LeafLabs
* board, and will only work properly if you follow the LeafLabs RCC
* configuration.
*
* @param us Number of microseconds to delay.
*/
static inline void delay_us(uint32 us) {
/* TODO this makes unwarranted assumptions about the RCC
* config; add a hook so users can make their own decisions. */
/* So (2^32)/12 micros max, or less than 6 minutes */
us *= 12;
/* fudge for function call overhead */
us--;
asm volatile(" mov r0, %[us] \n\t"
"1: subs r0, #1 \n\t"
" bhi 1b \n\t"
:
: [us] "r" (us)
: "r0");
}
#endif
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