722 B
722 B
v2.0 - "kajetanless" white PCB
#1: Programming header J6 has non-standard layout
Use a custom cable.
#2: R1 reset line resistor is pull-down
R1 footprint shall not be populated, and an equivalent resistor should be put in a pull-up configuration between reset line and ground.
Sensible place for that is between one C2 leg and reset line going next to it to J6 programming header.
#3: RS485 transceiver input/output enable is floating by default
This breaks programming serial communication, unless input/output enable pins are properly set.
This is fixed by applying optiboot patch - 0001-Disable-RS485-transceiver-when-running-the-bootloade.patch
v2.1 - "pulled-up" green PCB
Errata #2 fixed.