RPi 4 + UART no connection

General Discussion
1

Basic Information:

Printer Model: Elegoo Neptune 3 Pro
MCU / Printerboard: ZNP Robin Nano_DW V2.2
klippy.log

klippy_log.zip (1.6 MB)

I’m running Klipper on my Raspberry Pi 4 connected via USB to Neptune 3 Pro for quite some time now, but I’d rather use UART (will switch to Zero 2 W later).

I’m getting

mcu ‘mcu’: Unable to connect

Very similar to UART connection to RPi4?

raspi-gpio get output:

BANK0 (GPIO 0 to 27):
GPIO 0: level=1 fsel=0 func=INPUT pull=UP
GPIO 1: level=1 fsel=0 func=INPUT pull=UP
GPIO 2: level=1 fsel=4 alt=0 func=SDA1 pull=UP
GPIO 3: level=1 fsel=4 alt=0 func=SCL1 pull=UP
GPIO 4: level=1 fsel=0 func=INPUT pull=UP
GPIO 5: level=1 fsel=0 func=INPUT pull=UP
GPIO 6: level=1 fsel=0 func=INPUT pull=UP
GPIO 7: level=1 fsel=1 func=OUTPUT pull=UP
GPIO 8: level=1 fsel=1 func=OUTPUT pull=UP
GPIO 9: level=0 fsel=4 alt=0 func=SPI0_MISO pull=DOWN
GPIO 10: level=0 fsel=4 alt=0 func=SPI0_MOSI pull=DOWN
GPIO 11: level=0 fsel=4 alt=0 func=SPI0_SCLK pull=DOWN
GPIO 12: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 13: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 14: level=1 fsel=4 alt=0 func=TXD0 pull=NONE
GPIO 15: level=1 fsel=4 alt=0 func=RXD0 pull=UP
GPIO 16: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 17: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 18: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 19: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 20: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 21: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 22: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 23: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 24: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 25: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 26: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 27: level=0 fsel=0 func=INPUT pull=DOWN
BANK1 (GPIO 28 to 45):
GPIO 28: level=1 fsel=2 alt=5 func=RGMII_MDIO pull=UP
GPIO 29: level=0 fsel=2 alt=5 func=RGMII_MDC pull=DOWN
GPIO 30: level=0 fsel=0 func=INPUT pull=UP
GPIO 31: level=0 fsel=1 func=OUTPUT pull=NONE
GPIO 32: level=1 fsel=2 alt=5 func=TXD1 pull=NONE
GPIO 33: level=1 fsel=2 alt=5 func=RXD1 pull=UP
GPIO 34: level=1 fsel=7 alt=3 func=SD1_CLK pull=NONE
GPIO 35: level=1 fsel=7 alt=3 func=SD1_CMD pull=UP
GPIO 36: level=1 fsel=7 alt=3 func=SD1_DAT0 pull=UP
GPIO 37: level=0 fsel=7 alt=3 func=SD1_DAT1 pull=UP
GPIO 38: level=1 fsel=7 alt=3 func=SD1_DAT2 pull=UP
GPIO 39: level=1 fsel=7 alt=3 func=SD1_DAT3 pull=UP
GPIO 40: level=0 fsel=4 alt=0 func=PWM1_0 pull=NONE
GPIO 41: level=0 fsel=4 alt=0 func=PWM1_1 pull=NONE
GPIO 42: level=0 fsel=1 func=OUTPUT pull=UP
GPIO 43: level=1 fsel=0 func=INPUT pull=UP
GPIO 44: level=1 fsel=5 alt=1 func=SDA0 pull=UP
GPIO 45: level=1 fsel=5 alt=1 func=SCL0 pull=UP
BANK2 (GPIO 46 to 53):
GPIO 46: level=0 fsel=0 func=INPUT pull=UP
GPIO 47: level=0 fsel=0 func=INPUT pull=UP
GPIO 48: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 49: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 50: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 51: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 52: level=0 fsel=0 func=INPUT pull=DOWN
GPIO 53: level=0 fsel=0 func=INPUT pull=DOWN
2

Here is my printer.cfg printer_config.zip (3.2 KB)

3

cmdline.txt contains only:

console=tty1 root=PARTUUID=2a825920-02 rootfstype=ext4 fsck.repair=yes rootwait

4

You might want to refer to OctoKlipper - UART Cannot connect for a recent discussion it.

5

Well, guess who is a moron and skipped the clearly stated:

Select (Serial (on # USART2 PA3/PA2) if you want to use the serial UART pins on J17 (wifi section)

It works perfectly fine now! :slight_smile:

6

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