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Make sure the timer wraps around correctly independent of the os tick frequency

This commit is contained in:
Fred Sundvik 2018-06-22 20:10:20 +03:00 committed by Jack Humbert
parent 7acc781a01
commit c5db272c91

View file

@ -2,26 +2,40 @@
#include "timer.h" #include "timer.h"
void timer_init(void) {} static systime_t last_systime = 0;
static systime_t overflow = 0;
static uint32_t current_time_ms = 0;
void timer_clear(void) {} void timer_init(void) {
timer_clear();
uint16_t timer_read(void)
{
return (uint16_t)ST2MS(chVTGetSystemTime());
} }
uint32_t timer_read32(void) void timer_clear(void) {
{ last_systime = chVTGetSystemTime();
return ST2MS(chVTGetSystemTime()); overflow = 0;
current_time_ms = 0;
} }
uint16_t timer_elapsed(uint16_t last) uint16_t timer_read(void) {
{ return (uint16_t)timer_read32();
return (uint16_t)(ST2MS(chVTTimeElapsedSinceX(MS2ST(last))));
} }
uint32_t timer_elapsed32(uint32_t last) uint32_t timer_read32(void) {
{ // Note: We assume that the timer update is called at least once betweeen every wrap around of the system time
return ST2MS(chVTTimeElapsedSinceX(MS2ST(last))); systime_t current_systime = chVTGetSystemTime();
systime_t elapsed = current_systime - last_systime + overflow;
uint32_t elapsed_ms = ST2MS(elapsed);
current_time_ms += elapsed_ms;
overflow = elapsed - MS2ST(elapsed_ms);
last_systime = current_systime;
return current_time_ms;
}
uint16_t timer_elapsed(uint16_t last) {
return timer_read() - last;
}
uint32_t timer_elapsed32(uint32_t last) {
return timer_read32() - last;
} }