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authorFred Sundvik <fsundvik@gmail.com>2018-06-22 20:10:20 +0300
committerJack Humbert <jack.humb@gmail.com>2018-06-28 08:51:30 -0400
commitc5db272c911e886a0674bbf959b54e7b50c36636 (patch)
tree1a38a921bebf8b881892034d30b75e51c36e1871
parent7acc781a018d8190b8a14d36089f05c9ab855508 (diff)
Make sure the timer wraps around correctly independent of the os tick frequency
-rw-r--r--tmk_core/common/chibios/timer.c42
1 files changed, 28 insertions, 14 deletions
diff --git a/tmk_core/common/chibios/timer.c b/tmk_core/common/chibios/timer.c
index 3de4cc368b..473e533caa 100644
--- a/tmk_core/common/chibios/timer.c
+++ b/tmk_core/common/chibios/timer.c
@@ -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;
}