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AP_HAL_ChibiOS: correct prescaler algorithm

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remove redundant PWM reset
This commit is contained in:
Andy Piper 2022-02-06 16:05:23 +00:00 committed by Andrew Tridgell
parent ad30d476c8
commit ab25fc659a
1 changed files with 3 additions and 8 deletions
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11
libraries/AP_HAL_ChibiOS/RCOutput.cpp
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@ -773,11 +773,11 @@ bool RCOutput::setup_group_DMA(pwm_group &group, uint32_t bitrate, uint32_t bit_
// original prescaler calculation from betaflight. bi-dir dshot is incredibly sensitive to the bitrate
prescaler = uint32_t(lrintf((float) group.pwm_drv->clock / (bitrate * bit_width) + 0.01f) - 1);
} else {
// adjust frequency to give an allowed value given the clock.
// adjust frequency to give an allowed value given the clock, erring on the high side
const uint32_t clock_hz = group.pwm_drv->clock;
prescaler = group.pwm_drv->clock / target_frequency;
while ((clock_hz / prescaler) * prescaler != clock_hz && prescaler <= 0x8000) {
prescaler++;
while ((clock_hz / prescaler) < target_frequency && prescaler > 1) {
prescaler--;
}
}
@ -1918,11 +1918,6 @@ void RCOutput::serial_end(void)
irq.waiter = nullptr;
for (uint8_t i = 0; i < NUM_GROUPS; i++ ) {
pwm_group &group = pwm_group_list[i];
// restore normal output
if (group.pwm_started) {
pwmStop(group.pwm_drv);
group.pwm_started = false;
}
set_group_mode(group);
set_freq_group(group);
}