DiscEmu

A CD-ROM drive emulator based on Linux USB Gadget, on the Milk-V Duo (Original CV1800B variant) board.

Currently at prototype stage.

Hardware info

• Milk-V Duo board
• SSD1306 SPI 128x64 OLED
• EC11 rotary encoder

Pinout:

Function	Pin#
OLED MOSI	10
OLED SCK	9
OLED RES	22
OLED DC	21
EC11 S1	20
EC11 S2	19
EC11 KEY	18

Build

You can build this with the official SDK.

This app depends on the libu8g2arm library, please use my fork with Milk-V Duo GPIO pin number mapping. (GPIO pin number of Duo in Linux userspace are three digits, which break assumptions in libu8g2arm. A lookup table which maps Linux pin number to actual physical pin number is added as a workaround.)

Usage

• This app is statically linked by default, and should run fine on Milk-V Duo official images.

• run_usb.sh in this repo is modified from the official image, with CD-ROM support added, please use this verison with DiscEmu instead of the stock one.

• Place disc-emu and run_usb.sh at /mnt/data, and make it start at boot up by creating /mnt/data/auto.sh

OLD_PWD=$PWD
cd /mnt/data
nohup ./disc-emu
cd $OLD_PWD

• Disable RNDIS at boot up by removing /mnt/system/usb.sh to avoid conflicts. You can start RNDIS at the main menu of DiscEmu.

• DiscEmu looks for ISO images at isos in the working directory, so /mnt/data/isos as configured above. You might want to mount a partition with large enough space to this directory.

• Due to Linux kernel limitations, DVD images are not fully supported. Also there is a ~2.2GiB file size limit, there is a third-party patch to bypass this, see https://lkml.org/lkml/2015/3/7/388 for more details.