This resets the USARTs' clock source selection to the default, in case
it has been changed by the bootloader.
This is required if booting from the ArduPilot bootloader which happens
to reset the clock selection to PLL.
Without this fix, UARTs (including the console) is garbled, so
presumably at an invalid baudrate.
When flow control is used together with DMA, we need to add a pulldown
to CTS. Without it, it assumes flow control and gets stuck when
CTS is not connected.
Signed-off-by: Julian Oes <julian@oes.ch>
The defualt in NuttX is OSPEED of 50Mhz. This is realy a slew
rate control. At the default high slew rate the overshoot was
.7 Volts. On a ICM20649 this was causing the device to output
garbage. All 0s
N.B. A passive scope or Logic analyser's probes load will mask
the failure. Useed a FET probe to verify the issue.
Julian Oes