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>
- during casual testing on default configs the stack was penetration was reaching ~90% which is a bit too close for comfort
- increasing by 50% to be conservative
Julian Oes