stspin32g4: Add bootstrap capacitor charge mode on enable to avoid high side UVLO error on enable

[Moddingear]

This overrides the enable sequence on the stspin32g4:

The capacitors for the high side FETs need to be charged to drive the outputs high. Capacitors are charged by driving the low side mosfets ON.

If the voltage on the bootstrap capacitor goes below 5V while asking for the high side mosfet to be ON, this causes an undervoltage lockout on the high side FET, making them not conduct.

The high side UVLO isn't communicated back to the driver, as it's floating circuitry. But the Vds protection kick in, causing an error and disabling everything.

This adds a time when enabling where all the low side FETs are enabled, allowing for the caps to charge.

[github-actions]

Memory usage change @ 28242ce

Board	flash	%	RAM for global variables	%
adafruit:samd:adafruit_metro_m4	0 - 0	0.0 - 0.0	N/A	N/A
arduino:avr:nano	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0
rp2040:rp2040:rpipico	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0
arduino:sam:arduino_due_x	0 - 0	0.0 - 0.0	N/A	N/A
arduino:samd:nano_33_iot	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0
esp32:esp32:esp32	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0
esp32:esp32:esp32s2	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0
STMicroelectronics:stm32:GenF1:pnum=BLUEPILL_F103C8	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0
STMicroelectronics:stm32:Nucleo_64:pnum=NUCLEO_F411RE	0 - 0	0.0 - 0.0	0 - 0	0.0 - 0.0

Click for full report table

Board	examples/drivers/drv8316/drv8316_3pwm flash	%	examples/drivers/drv8316/drv8316_3pwm RAM for global variables	%	examples/drivers/drv8316/drv8316_6pwm flash	%	examples/drivers/drv8316/drv8316_6pwm RAM for global variables	%	examples/encoders/calibrated_sensor/calibration_save flash	%	examples/encoders/calibrated_sensor/calibration_save RAM for global variables	%	examples/encoders/linearhall flash	%	examples/encoders/linearhall RAM for global variables	%	examples/encoders/mt6816/mt6816_spi flash	%	examples/encoders/mt6816/mt6816_spi RAM for global variables	%	examples/drivers/simplefocnano/simplefocnano_atmega flash	%	examples/drivers/simplefocnano/simplefocnano_atmega RAM for global variables	%	examples/encoders/calibrated_sensor/calibrated flash	%	examples/encoders/calibrated_sensor/calibrated RAM for global variables	%
adafruit:samd:adafruit_metro_m4	0	0.0	N/A	N/A	0	0.0	N/A	N/A	0	0.0	N/A	N/A	0	0.0	N/A	N/A	0	0.0	N/A	N/A
arduino:avr:nano													0	0.0	0	0.0					0	0.0	0	0.0
rp2040:rp2040:rpipico	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
arduino:sam:arduino_due_x	0	0.0	N/A	N/A	0	0.0	N/A	N/A	0	0.0	N/A	N/A	0	0.0	N/A	N/A	0	0.0	N/A	N/A
arduino:samd:nano_33_iot	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
esp32:esp32:esp32	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0					0	0.0	0	0.0
esp32:esp32:esp32s2	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
STMicroelectronics:stm32:GenF1:pnum=BLUEPILL_F103C8	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0
STMicroelectronics:stm32:Nucleo_64:pnum=NUCLEO_F411RE	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0					0	0.0	0	0.0

Click for full report CSV

Board,examples/drivers/drv8316/drv8316_3pwm<br>flash,%,examples/drivers/drv8316/drv8316_3pwm<br>RAM for global variables,%,examples/drivers/drv8316/drv8316_6pwm<br>flash,%,examples/drivers/drv8316/drv8316_6pwm<br>RAM for global variables,%,examples/encoders/calibrated_sensor/calibration_save<br>flash,%,examples/encoders/calibrated_sensor/calibration_save<br>RAM for global variables,%,examples/encoders/linearhall<br>flash,%,examples/encoders/linearhall<br>RAM for global variables,%,examples/encoders/mt6816/mt6816_spi<br>flash,%,examples/encoders/mt6816/mt6816_spi<br>RAM for global variables,%,examples/drivers/simplefocnano/simplefocnano_atmega<br>flash,%,examples/drivers/simplefocnano/simplefocnano_atmega<br>RAM for global variables,%,examples/encoders/calibrated_sensor/calibrated<br>flash,%,examples/encoders/calibrated_sensor/calibrated<br>RAM for global variables,%
adafruit:samd:adafruit_metro_m4,0,0.0,N/A,N/A,0,0.0,N/A,N/A,0,0.0,N/A,N/A,0,0.0,N/A,N/A,0,0.0,N/A,N/A
arduino:avr:nano,,,,,,,,,,,,,0,0.0,0,0.0,,,,,0,0.0,0,0.0
rp2040:rp2040:rpipico,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,,,,
arduino:sam:arduino_due_x,0,0.0,N/A,N/A,0,0.0,N/A,N/A,0,0.0,N/A,N/A,0,0.0,N/A,N/A,0,0.0,N/A,N/A,,,,
arduino:samd:nano_33_iot,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,,,,
esp32:esp32:esp32,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,,,,,0,0.0,0,0.0,,,,
esp32:esp32:esp32s2,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,,,,
STMicroelectronics:stm32:GenF1:pnum=BLUEPILL_F103C8,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,,,,,,,,
STMicroelectronics:stm32:Nucleo_64:pnum=NUCLEO_F411RE,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,0,0.0,,,,,0,0.0,0,0.0

[runger1101001]

Thank you for contributing this. I remember the discussion on Discord.

I'd like to understand the rationale a little better:

• this problem occurs for you when you disable the motor, as this puts the gates in Hi-Z mode and the bootstrap cap can't recharge/slowly discharges.
• its often desirable to have a disable function rather than just setting target voltage to 0, since this will run the modulation which will cause noise on some motors.
• another option would be to use the setPhaseState or setPhaseVoltage functions to set the low side to be on. But this would brake the motor more than hi-z mode does, so may also not be desirable in some situations.

so it seems pre-charging the bootstrap capacitors is a valid strategy for some use-cases.

• however in some cases it may not be wanted, so it would be nice to have it more optional in the code
• it gets called on enable and on init but that may be redundant since I think enable() has to be called after init anyway
• it doesn't get called on wake, but I think it might need to be

[runger1101001]

I'm wondering if we should add another setPwm here to actually apply the restored phase state.

But I'm also wondering about the purpose of remembering and restoring at all?

[Moddingear]

Yeah, a SetPWM should probably be called, I figured it wouldn't hurt to leave it in the charge state...

As for remembering and restoring, the logic was that this code would leave the driver in the same state as it found it, and would skip charging if it was already activated...