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AP_HAL_ChibiOS: modify prescaler based on dshot type

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This commit is contained in:
Andy Piper 2023-09-17 12:30:04 +01:00 committed by Andrew Tridgell
parent 5c0f049739
commit 36fc7521ea
2 changed files with 20 additions and 11 deletions
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29
libraries/AP_HAL_ChibiOS/RCOutput.cpp
View File

@ -912,7 +912,7 @@ void RCOutput::print_group_setup_error(pwm_group &group, const char* error_strin
This is used for both DShot and serial output
*/
bool RCOutput::setup_group_DMA(pwm_group &group, uint32_t bitrate, uint32_t bit_width, bool active_high, const uint16_t buffer_length,
uint32_t pulse_time_us, bool is_dshot)
uint32_t pulse_time_us, bool at_least_freq)
{
#if HAL_DSHOT_ENABLED
// for dshot we setup for DMAR based output
@ -976,7 +976,8 @@ bool RCOutput::setup_group_DMA(pwm_group &group, uint32_t bitrate, uint32_t bit_
group.pwm_started = false;
}
const uint32_t target_frequency = bitrate * bit_width;
const uint32_t prescaler = calculate_bitrate_prescaler(group.pwm_drv->clock, target_frequency, is_dshot);
const uint32_t prescaler = calculate_bitrate_prescaler(group.pwm_drv->clock, target_frequency, at_least_freq);
if (prescaler == 0 || prescaler > 0x8000) {
#if AP_HAL_SHARED_DMA_ENABLED
group.dma_handle->unlock();
@ -993,13 +994,13 @@ bool RCOutput::setup_group_DMA(pwm_group &group, uint32_t bitrate, uint32_t bit_
group.bit_width_mul = (freq + (target_frequency/2)) / target_frequency;
// ARR is calculated by ChibiOS as pwm_cfg.period -1
group.pwm_cfg.period = bit_width * group.bit_width_mul;
//hal.console->printf("CLOCK=%u BW=%u FREQ=%u BR=%u MUL=%u PRE=%u\n", unsigned(group.pwm_drv->clock), unsigned(bit_width), unsigned(group.pwm_cfg.frequency),
// unsigned(bitrate), unsigned(group.bit_width_mul), unsigned(prescaler));
//static char clock_setup[64];
//hal.util->snprintf(clock_setup, 64, "CLOCK=%u BW=%u FREQ=%u BR=%u MUL=%u PRE=%u\n", unsigned(group.pwm_drv->clock), unsigned(bit_width), unsigned(group.pwm_cfg.frequency),
// unsigned(bitrate), unsigned(group.bit_width_mul), unsigned(prescaler));
#if 0
hal.console->printf("CLOCK=%u BW=%u FREQ=%u BR=%u MUL=%u PRE=%u\n", unsigned(group.pwm_drv->clock), unsigned(bit_width), unsigned(group.pwm_cfg.frequency),
unsigned(bitrate), unsigned(group.bit_width_mul), unsigned(prescaler));
static char clock_setup[64];
hal.util->snprintf(clock_setup, 64, "CLOCK=%u BW=%u FREQ=%u BR=%u MUL=%u PRE=%u\n", unsigned(group.pwm_drv->clock), unsigned(bit_width), unsigned(group.pwm_cfg.frequency),
unsigned(bitrate), unsigned(group.bit_width_mul), unsigned(prescaler));
#endif
for (uint8_t j=0; j<4; j++) {
pwmmode_t mode = group.pwm_cfg.channels[j].mode;
if (mode != PWM_OUTPUT_DISABLED) {
@ -1091,14 +1092,21 @@ void RCOutput::set_group_mode(pwm_group &group)
#endif
case MODE_PWM_DSHOT150 ... MODE_PWM_DSHOT1200: {
#if HAL_DSHOT_ENABLED
const uint32_t rate = protocol_bitrate(group.current_mode);
bool active_high = is_bidir_dshot_enabled() ? false : true;
bool at_least_freq = false;
// calculate min time between pulses
const uint32_t pulse_send_time_us = 1000000UL * dshot_bit_length / rate;
// BLHeli_S (and BlueJay) appears to always want the frequency above the target
if (_dshot_esc_type == DSHOT_ESC_BLHELI_S || _dshot_esc_type == DSHOT_ESC_BLHELI_EDT_S) {
at_least_freq = true;
}
// configure timer driver for DMAR at requested rate
if (!setup_group_DMA(group, rate, DSHOT_BIT_WIDTH_TICKS, active_high,
MAX(DSHOT_BUFFER_LENGTH, GCR_TELEMETRY_BUFFER_LEN), pulse_send_time_us, true)) {
MAX(DSHOT_BUFFER_LENGTH, GCR_TELEMETRY_BUFFER_LEN), pulse_send_time_us, at_least_freq)) {
group.current_mode = MODE_PWM_NORMAL;
break;
}
@ -1107,6 +1115,7 @@ void RCOutput::set_group_mode(pwm_group &group)
// to all intents and purposes the pulse time of send and receive are the same
group.dshot_pulse_time_us = pulse_send_time_us + pulse_send_time_us + 30;
}
#endif
break;
}

2
libraries/AP_HAL_ChibiOS/RCOutput.h
View File

@ -657,7 +657,7 @@ private:
bool mode_requires_dma(enum output_mode mode) const;
bool setup_group_DMA(pwm_group &group, uint32_t bitrate, uint32_t bit_width, bool active_high,
const uint16_t buffer_length, uint32_t pulse_time_us,
bool is_dshot);
bool at_least_freq);
void send_pulses_DMAR(pwm_group &group, uint32_t buffer_length);
void set_group_mode(pwm_group &group);
static uint32_t protocol_bitrate(const enum output_mode mode);