Context

• See hibernate-pocket, hibernate-pocket-2

Serial console hardware

• Manual is unclear about name of connector (J16 in schematics, J17 in manual).
• Also numbering of pins is not given afaict.
• Clone https://source.mnt.re/reform/pocket-reform.git
• Look at pocket-reform-motherboard.kicad_pcb
• From the PCB I can confirm J16 and pins numbered left (sysctl) to right.
• attach "dtech" prolific PL2303 based serial to usb cable per serial console section of PR manual
• lsusb shows ID 067b:23a3 Prolific Technology, Inc. ATEN Serial Bridge
• install tio
• add my user to group dialout
• newgrp dialout
• tio /dev/ttyUSB0 -b 1500000
• A closer look at the PCB in kicad makes me realize the pin labels in the manual are wrong. 4 = GND, 5 = UART1_RX, 6= UART1_TX. With that change I have U-boot output on boot.

Serial console software

With some help from minute on ircs://irc.libera.chat:6697/#mnt-reform, I got the kernel boot arguments right to have not just u-boot output but linux kernel output on the serial console. In consfigurator notation

(on-change
      (file:has-content "/etc/flash-kernel/ubootenv.d/00reform2_serial_console"
        "setenv bootargs \"${bootargs} console=ttyS2,1500000 keep_bootcon\"")
    (cmd:single "flash-kernel"))

The filename should sort before "00reform2_ubootenv" so that the existing "console=tty1" still ends up at the end.

previous episode|next episode