From 2728603fe6d73e805a539d337fd01051c46ca806 Mon Sep 17 00:00:00 2001 From: Joel Challis Date: Fri, 19 Nov 2021 18:41:02 +0000 Subject: Move tmk_core/common/ (#13918) --- platforms/chibios/timer.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 platforms/chibios/timer.c (limited to 'platforms/chibios/timer.c') diff --git a/platforms/chibios/timer.c b/platforms/chibios/timer.c new file mode 100644 index 0000000000..9f664e1f79 --- /dev/null +++ b/platforms/chibios/timer.c @@ -0,0 +1,47 @@ +#include + +#include "timer.h" + +static uint32_t reset_point = 0; +#if CH_CFG_ST_RESOLUTION < 32 +static uint32_t last_systime = 0; +static uint32_t overflow = 0; +#endif + +void timer_init(void) { timer_clear(); } + +void timer_clear(void) { + reset_point = (uint32_t)chVTGetSystemTime(); +#if CH_CFG_ST_RESOLUTION < 32 + last_systime = reset_point; + overflow = 0; +#endif +} + +uint16_t timer_read(void) { return (uint16_t)timer_read32(); } + +uint32_t timer_read32(void) { + uint32_t systime = (uint32_t)chVTGetSystemTime(); + +#if CH_CFG_ST_RESOLUTION < 32 + // If/when we need to support 64-bit chips, this may need to be modified to match the native bit-ness of the MCU. + // At this point, the only SysTick resolution allowed other than 32 is 16 bit. + // In the 16-bit case, at: + // - CH_CFG_ST_FREQUENCY = 100000, overflow will occur every ~0.65 seconds + // - CH_CFG_ST_FREQUENCY = 10000, overflow will occur every ~6.5 seconds + // - CH_CFG_ST_FREQUENCY = 1000, overflow will occur every ~65 seconds + // With this implementation, as long as we ensure a timer read happens at least once during the overflow period, timing should be accurate. + if (systime < last_systime) { + overflow += ((uint32_t)1) << CH_CFG_ST_RESOLUTION; + } + + last_systime = systime; + return (uint32_t)TIME_I2MS(systime - reset_point + overflow); +#else + return (uint32_t)TIME_I2MS(systime - reset_point); +#endif +} + +uint16_t timer_elapsed(uint16_t last) { return TIMER_DIFF_16(timer_read(), last); } + +uint32_t timer_elapsed32(uint32_t last) { return TIMER_DIFF_32(timer_read32(), last); } -- cgit v1.2.3