Commit | Line | Data |
---|---|---|
4d4f7684 | 1 | #include "ch.h" |
2 | ||
3 | #include "timer.h" | |
4 | ||
26eef35f JY |
5 | static uint32_t reset_point = 0; |
6 | #if CH_CFG_ST_RESOLUTION < 32 | |
7 | static uint32_t last_systime = 0; | |
8 | static uint32_t overflow = 0; | |
9 | #endif | |
4d4f7684 | 10 | |
b624f32f | 11 | void timer_init(void) { timer_clear(); } |
c5db272c FS |
12 | |
13 | void timer_clear(void) { | |
26eef35f JY |
14 | reset_point = (uint32_t)chVTGetSystemTime(); |
15 | #if CH_CFG_ST_RESOLUTION < 32 | |
16 | last_systime = reset_point; | |
17 | overflow = 0; | |
18 | #endif | |
c5db272c | 19 | } |
4d4f7684 | 20 | |
b624f32f | 21 | uint16_t timer_read(void) { return (uint16_t)timer_read32(); } |
4d4f7684 | 22 | |
c5db272c | 23 | uint32_t timer_read32(void) { |
26eef35f JY |
24 | uint32_t systime = (uint32_t)chVTGetSystemTime(); |
25 | ||
26 | #if CH_CFG_ST_RESOLUTION < 32 | |
27 | // If/when we need to support 64-bit chips, this may need to be modified to match the native bit-ness of the MCU. | |
28 | // At this point, the only SysTick resolution allowed other than 32 is 16 bit. | |
29 | // In the 16-bit case, at: | |
30 | // - CH_CFG_ST_FREQUENCY = 100000, overflow will occur every ~0.65 seconds | |
31 | // - CH_CFG_ST_FREQUENCY = 10000, overflow will occur every ~6.5 seconds | |
32 | // - CH_CFG_ST_FREQUENCY = 1000, overflow will occur every ~65 seconds | |
33 | // With this implementation, as long as we ensure a timer read happens at least once during the overflow period, timing should be accurate. | |
34 | if (systime < last_systime) { | |
35 | overflow += ((uint32_t)1) << CH_CFG_ST_RESOLUTION; | |
36 | } | |
37 | ||
38 | last_systime = systime; | |
39 | return (uint32_t)TIME_I2MS(systime - reset_point + overflow); | |
40 | #else | |
41 | return (uint32_t)TIME_I2MS(systime - reset_point); | |
42 | #endif | |
4d4f7684 | 43 | } |
44 | ||
1a79f14e | 45 | uint16_t timer_elapsed(uint16_t last) { return TIMER_DIFF_16(timer_read(), last); } |
4d4f7684 | 46 | |
1a79f14e | 47 | uint32_t timer_elapsed32(uint32_t last) { return TIMER_DIFF_32(timer_read32(), last); } |