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AP_ChibiOS: handle oneshot125 separately

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this sets up oneshot125 with the full 1000 steps of throttle
resolution, using a 8MHz clock. This matches the behaviour of modern
ESCs that measure PWM values with high accuracy
This commit is contained in:
Andrew Tridgell 2018-04-03 18:13:41 +10:00
parent 819de4acd5
commit 3cd4f2a002
2 changed files with 52 additions and 17 deletions
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66
libraries/AP_HAL_ChibiOS/RCOutput.cpp
View File

@ -51,7 +51,6 @@ void RCOutput::init()
for (uint8_t i = 0; i < NUM_GROUPS; i++ ) {
//Start Pwm groups
pwm_group &group = pwm_group_list[i];
group.ch_mask = 0;
group.current_mode = MODE_PWM_NORMAL;
for (uint8_t j = 0; j < 4; j++ ) {
if (group.chan[j] != CHAN_DISABLED) {
@ -91,9 +90,12 @@ void RCOutput::set_freq_group(pwm_group &group)
uint16_t freq_set = group.rc_frequency;
uint32_t old_clock = group.pwm_cfg.frequency;
uint32_t old_period = group.pwm_cfg.period;
if (freq_set > 400) {
// use a 8MHz clock
if (freq_set > 400 || group.current_mode == MODE_PWM_ONESHOT125) {
// use a 8MHz clock for higher frequencies or for
// oneshot125. Using 8MHz for oneshot125 results in the full
// 1000 steps for smooth output
group.pwm_cfg.frequency = 8000000;
} else if (freq_set <= 400) {
// use a 1MHz clock
@ -112,7 +114,13 @@ void RCOutput::set_freq_group(pwm_group &group)
psc = (pwmp->clock / pwmp->config->frequency) - 1;
}
group.pwm_cfg.period = group.pwm_cfg.frequency/freq_set;
if (group.current_mode == MODE_PWM_ONESHOT ||
group.current_mode == MODE_PWM_ONESHOT125) {
// force a period of 0, meaning no pulses till we trigger
group.pwm_cfg.period = 0;
} else {
group.pwm_cfg.period = group.pwm_cfg.frequency/freq_set;
}
bool force_reconfig = false;
for (uint8_t j=0; j<4; j++) {
@ -122,7 +130,10 @@ void RCOutput::set_freq_group(pwm_group &group)
}
}
if (old_clock != group.pwm_cfg.frequency || !group.pwm_started || force_reconfig) {
if (old_clock != group.pwm_cfg.frequency ||
old_period != group.pwm_cfg.period ||
!group.pwm_started ||
force_reconfig) {
// we need to stop and start to setup the new clock
if (group.pwm_started) {
pwmStop(group.pwm_drv);
@ -281,7 +292,13 @@ void RCOutput::write(uint8_t chan, uint16_t period_us)
#if HAL_WITH_IO_MCU
// handle IO MCU channels
if (AP_BoardConfig::io_enabled()) {
iomcu.write_channel(chan, period_us);
uint16_t io_period_us = period_us;
if (iomcu_oneshot125) {
// the iomcu only has one oneshot setting, so we need to scale by a factor
// of 8 here for oneshot125
io_period_us /= 8;
}
iomcu.write_channel(chan, io_period_us);
}
#endif
if (chan < chan_offset) {
@ -335,6 +352,10 @@ void RCOutput::push_local(void)
(_esc_pwm_max - _esc_pwm_min), (period_us - _esc_pwm_min));
}
pwmEnableChannel(group.pwm_drv, j, period_us);
} else if (group.current_mode == MODE_PWM_ONESHOT125) {
// this gives us a width in 125 ns increments, giving 1000 steps over the 125 to 250 range
uint32_t width = ((group.pwm_cfg.frequency/1000000U) * period_us) / 8U;
pwmEnableChannel(group.pwm_drv, j, width);
} else if (group.current_mode < MODE_PWM_DSHOT150) {
uint32_t width = (group.pwm_cfg.frequency/1000000U) * period_us;
pwmEnableChannel(group.pwm_drv, j, width);
@ -346,6 +367,7 @@ void RCOutput::push_local(void)
widest_pulse = period_us;
}
if (group.current_mode == MODE_PWM_ONESHOT ||
group.current_mode == MODE_PWM_ONESHOT125 ||
(group.current_mode >= MODE_PWM_DSHOT150 &&
group.current_mode <= MODE_PWM_DSHOT1200)) {
need_trigger |= (1U<<i);
@ -547,8 +569,9 @@ void RCOutput::set_group_mode(pwm_group &group)
}
case MODE_PWM_ONESHOT:
// for oneshot we force 1Hz output and then trigger on each loop
group.pwm_cfg.period = group.pwm_cfg.frequency;
case MODE_PWM_ONESHOT125:
// for oneshot we set a period of 0, which results in no pulses till we trigger
group.pwm_cfg.period = 0;
group.rc_frequency = 1;
if (group.pwm_started) {
pwmChangePeriod(group.pwm_drv, group.pwm_cfg.period);
@ -561,6 +584,8 @@ void RCOutput::set_group_mode(pwm_group &group)
break;
}
set_freq_group(group);
if (group.current_mode != MODE_PWM_NONE &&
!group.pwm_started) {
pwmStart(group.pwm_drv, &group.pwm_cfg);
@ -587,13 +612,20 @@ void RCOutput::set_output_mode(uint16_t mask, enum output_mode mode)
if (mode_requires_dma(mode) && !group.have_up_dma) {
mode = MODE_PWM_NONE;
}
group.current_mode = mode;
set_group_mode(group);
if (group.current_mode != mode) {
group.current_mode = mode;
set_group_mode(group);
}
}
#if HAL_WITH_IO_MCU
if (mode == MODE_PWM_ONESHOT &&
if ((mode == MODE_PWM_ONESHOT ||
mode == MODE_PWM_ONESHOT125) &&
(mask & ((1U<<chan_offset)-1)) &&
AP_BoardConfig::io_enabled()) {
iomcu_oneshot125 = (mode == MODE_PWM_ONESHOT125);
// also setup IO to use a 1Hz frequency, so we only get output
// when we trigger
iomcu.set_freq(0xFF, 1);
return iomcu.set_oneshot_mode();
}
#endif
@ -685,7 +717,8 @@ void RCOutput::trigger_groups(void)
// doing serial output, don't send pulses
continue;
}
if (group.current_mode == MODE_PWM_ONESHOT) {
if (group.current_mode == MODE_PWM_ONESHOT ||
group.current_mode == MODE_PWM_ONESHOT125) {
if (trigger_groupmask & (1U<<i)) {
// this triggers pulse output for a channel group
group.pwm_drv->tim->EGR = STM32_TIM_EGR_UG;
@ -737,16 +770,15 @@ void RCOutput::timer_tick(void)
dshot_send(group, true);
}
}
if (trigger_groupmask == 0 ||
min_pulse_trigger_us == 0 ||
if (min_pulse_trigger_us == 0 ||
serial_group != nullptr) {
return;
}
if (now > min_pulse_trigger_us &&
now - min_pulse_trigger_us > 10000) {
// trigger at a minimum of 100Hz
now - min_pulse_trigger_us > 4000) {
// trigger at a minimum of 250Hz
trigger_groups();
}
}
}
/*

3
libraries/AP_HAL_ChibiOS/RCOutput.h
View File

@ -227,6 +227,9 @@ private:
// widest pulse for oneshot triggering
uint16_t trigger_widest_pulse;
// are we using oneshot125 for the iomcu?
bool iomcu_oneshot125;
// push out values to local PWM
void push_local(void);