~ruther/qmk_firmware

c5db272c911e886a0674bbf959b54e7b50c36636 — Fred Sundvik 7 years ago 7acc781
Make sure the timer wraps around correctly independent of the os tick frequency
1 files changed, 28 insertions(+), 14 deletions(-)

M tmk_core/common/chibios/timer.c
M tmk_core/common/chibios/timer.c => tmk_core/common/chibios/timer.c +28 -14
@@ 2,26 2,40 @@

#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();
}

void timer_clear(void) {
  last_systime = chVTGetSystemTime();
  overflow = 0;
  current_time_ms = 0;
}

uint16_t timer_read(void)
{
    return (uint16_t)ST2MS(chVTGetSystemTime());
uint16_t timer_read(void) {
  return (uint16_t)timer_read32();
}

uint32_t timer_read32(void)
{
    return ST2MS(chVTGetSystemTime());
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
  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 (uint16_t)(ST2MS(chVTTimeElapsedSinceX(MS2ST(last))));
uint16_t timer_elapsed(uint16_t last) {
  return timer_read() - last;
}

uint32_t timer_elapsed32(uint32_t last)
{
    return ST2MS(chVTTimeElapsedSinceX(MS2ST(last)));
uint32_t timer_elapsed32(uint32_t last) {
  return timer_read32() - last;
}