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clean up timer_set_rate and add advice on hacking counter frequency

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This commit is contained in:
Mark Whitehorn
2017-02-19 15:50:53 -07:00
committed by Lorenz Meier
parent 2d5588ae02
commit dd25366b86
1 changed files with 5 additions and 15 deletions
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20
src/drivers/stm32/drv_io_timer.c
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@@ -378,7 +378,10 @@ static int allocate_channel(unsigned channel, io_timer_channel_mode_t mode)
static int timer_set_rate(unsigned timer, unsigned rate)
{
/* configure the timer to update at the desired rate */
/* Configure the timer to run at 1MHz (other system code _assumes_ that timers run at 1MHz).
* If you want to hack this to achieve a different frequency, alter the value of
* .clock_freq in the relevant driver/boards/xxxx/xxx_timer_config.c file.
*/
timer_freq[timer] = 1;
rPSC(timer) = (io_timers[timer].clock_freq / 1000000) - 1;
rARR(timer) = timer_freq[timer] * 1000000 / rate;
@@ -391,6 +394,7 @@ static int timer_set_rate(unsigned timer, unsigned rate)
void io_timer_set_oneshot_mode(unsigned timer)
{
/* This timer MUST run at 8MHz */
timer_freq[timer] = 8;
rPSC(timer) = (io_timers[timer].clock_freq / 8000000) - 1;
@@ -452,20 +456,6 @@ int io_timer_init_timer(unsigned timer)
rBDTR(timer) = ATIM_BDTR_MOE;
}
/* If in oneshot mode, configure the prescaler for 8MHz output.
* else set prescaler for 1MHz.
*/
if (timer_freq[timer] == 8) {
rPSC(timer) = (io_timers[timer].clock_freq / 8000000) - 1;
// can't find a way to trigger in this mode
// /* set one pulse mode */
// rCR1(timer) |= 1 << 3;
} else {
rPSC(timer) = (io_timers[timer].clock_freq / 1000000) - 1;
}
/*
* Note we do the Standard PWM Out init here
* default to updating at 50Hz