enable slew-rate control to prevent overcurrent

[arthurbenemann]

Slew-rate limited

No slew-rate (v1.0.0 software)

[arthurbenemann]

Some extra screenshots showing the current on the system. The displayed currents are double because of limitations on the test setup.

Factory software

Slew rate control

[AJHong]

Note: Here in the lab, we have seen 3 Solos where the I2C has failed with the slew-rate ESC firmware. Symptoms have been all green LEDs, and no Battery telemetry.
When we try and flash these ESCs back to "E2" factory firmware, we have seen a cases where the ESC will short out when powered on by Solo.
My best guess would be some hardware component is being damaged while slew ESC firmware is loaded, and when you reflash to E2 firmware it shorts out that component.

[sim-]

Do you have pull-downs on the drive pins to prevent them from floating or staying on when the MCU is tristated? This is a critical piece that is sometimes overlooked. If you are using the bs_nfet pin arrangement, the high side is inverted, which means that all high-side FETs will be on if the MCU tristates, but there definitely needs to still be a path to drain the gates of the low-side FETs to prevent shoot-through.

[arthurbenemann]

This is the bridge arrangement (PC3/PB0 are connected straight to the MCU):

There doesn't seem to be any pull-down resistors. A shoot -though would explain the high-current spikes