djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

stmhal: Reset the timer counter to zero after changing the auto reload.

Browse Source 
Because if the counter is above the new value of the auto-reload register
then it may be a long time until the timer wraps around.
This commit is contained in:
Dave Hylands 2015-04-22 15:01:25 -07:00 committed by Damien George
parent 40d43ea88d
commit fd787c5e4e
1 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
stmhal/timer.c
View File

@ -1088,6 +1088,10 @@ STATIC mp_obj_t pyb_timer_freq(mp_uint_t n_args, const mp_obj_t *args) {
uint32_t prescaler = compute_prescaler_period_from_freq(self, args[1], &period);
self->tim.Instance->PSC = prescaler;
__HAL_TIM_SetAutoreload(&self->tim, period);
// Reset the counter to zero. Otherwise, if counter >= period it will
// continue counting until it wraps (at either 16 or 32 bits depending
// on the timer).
__HAL_TIM_SetCounter(&self->tim, 0);
return mp_const_none;
}
}
@ -1118,6 +1122,10 @@ STATIC mp_obj_t pyb_timer_period(mp_uint_t n_args, const mp_obj_t *args) {
} else {
// set
__HAL_TIM_SetAutoreload(&self->tim, mp_obj_get_int(args[1]) & TIMER_CNT_MASK(self));
// Reset the counter to zero. Otherwise, if counter >= period it will
// continue counting until it wraps (at either 16 or 32 bits depending
// on the timer).
__HAL_TIM_SetCounter(&self->tim, 0);
return mp_const_none;
}
}