The Mega EverDrive PRO has a USB port (much like the EverDrive X7) which allows you to send arbitary data to the Mega Drive over USB. With the X7 you could simply send data to the USB serial device and pick it up at a specific memory mapped location on the Mega Drive. With the PRO, however, you need to wrap the data in a "command" and send it over the USB serial device, so that it will be available to the Mega Drive.
The following information was obtained by reading the source contained in the MEGA-PRO repo.
| Field | Bytes | Value (hex) | Description |
|---|---|---|---|
| Preamble | 0 | 2B | A plus (+) symbol |
| Preamble Inverted | 1 | D4 | Previous byte with bits inverted |
| Command Type | 2 | 1A | CMD_MEM_RW |
| Command Type Inverted | 3 | E5 | Previous byte with bits inverted |
| Memory Location | 4-7 | 01 81 00 00 | ADDR_FIFO |
| Data Length | 8-11 | 00 00 00 05 | Length of data (for example, 5) |
| Padding | 12 | 00 | Padding |
| Data | 13+ | 65 65 65 65 65 | The data itself (for example, eeeee) |
- Load up the
megaio-appROM on the Mega Drive. - Select
usb read. - On a Unix machine with the ED PRO connected via USB, create a binary file (
message.txt) with the bytes described above. - Run
cat message.txt > /dev/cu.usbmodem00000000001A1(or to whatever the USB serial device is called) - The message
eeeeeshould appear on the Mega Drive screen.