Check the following:
-
the serial port really exists and named properly in ./dev/serial/ folder
-
use a serial monitor and check if there are any messages from printer to raspberry.
OR (the way I’ve done during the checking) -
remove bottom cover from cpu bay on your printer
-
solder any spst button between RST and GND contacts
-
connect board to any serial monitor, establish connection with following settings: Speed 115200; Data bits: 1; Stop bits: 1; Parity - none;- and restart Kobra2 CPU - you should see a bootloader greeting and message something like “firmware on SD card not found , continue to mail program at 0x10000” and after that you should see some strange symbols (in my case starting with 92 or 93). If there are nothing after message from bootloader, please double check that you compile a firmware on klipper with correct offset settings, correct pins(15 and 9) and 168MHz frequency.
