Using minicom with an empeg

13 Jun 2022 13:38 empeg minicom

It’s been many years since I last connected my empeg player to a Linux PC, and the muscle memory’s gone. Here’s how to make it work with Ubuntu 20.04.

Install minicom

sudo apt install minicom

Configure udev

I’m using a “Magic Control Technology Corp. MCT-232 Serial Port” USB-to-serial converter, with a null-modem cable. When connected to the Linux PC, it appears as /dev/ttyUSB0, but the permissions don’t allow access. We can configure udev to fix this up.

Based on my answer about adb permissions here, I went with the following:

First, we need the USB VID and PID for the adapter:

$ lsusb
Bus 001 Device 004: ID 0711:0230 Magic Control Technology Corp. MCT-232 Serial Port

Then we create /etc/udev/rules.d/80-mct232.rules:

ATTRS{idVendor}=="0711", ATTRS{idProduct}=="0230", MODE="0664", GROUP="plugdev"

Restart udev:

$ sudo udevadm control --reload-rules
$ sudo service udev restart

Unplug/replug your device. It should appear as /dev/ttyUSB0 owned by the plugdev group.

Run minicom

The following will sort of work:

minicom -D /dev/ttyUSB0 -b 115200

But we’ll need to tweak various other settings, so, following https://www.centennialsoftwaresolutions.com/post/configure-minicom-for-a-usb-to-serial-converter:

  1. Press Ctrl+A, O (upper-case O-for-Oscar) to bring up the configuration.
  2. Select “Serial port setup”.
  3. Serial device: /dev/ttyUSB0.
  4. Bps/Par/Bits: 115200 8N1.
  5. Hardware flow control: No.
  6. Software flow control: No.
  7. Press Enter to return to the configuration menu.
  8. Choose “Save setup as dfl”.

Or just create ~/.minirc.dfl as follows:

# Machine-generated file - use setup menu in minicom to change parameters.
pu port             /dev/ttyUSB0
pu baudrate         115200
pu bits             8
pu parity           N
pu stopbits         1
pu rtscts           No
pu xonxoff          No

(Yes, I know it’s not actually machine-generated…)

Then you can just run minicom.

Interacting with the device

By default, the player doesn’t output anything to the serial port, so it’ll look like nothing’s happening. If you power-cycle it, you should see the boot messages. If you press Ctrl+C, you should be dropped to the bash prompt. Exiting from bash should restart the player.

For a list of serial port commands, see this page.

Quitting minicom

Press Ctrl+A, X.

Windows?

I initially attempted to use the converter with Windows, but there are apparently no drivers for Windows 11, so that’s a non-starter.