Support using a ModRetro Chromatic as a dumper

[fredemmott]

Requires https://github.com/fredemmott/chromatic_dumper firmware loaded into FPGA RAM, but not ROM.

If you're interested in taking this, the next step would be to automatically load the firmware with openfpgaloader. For now, I'm using the gowin IDE to load it before starting FlashGBX.

Given that changing cartridges requires turning off the chromatic, turning it on, and loading the firmware again every time, it would probably be best to automatically load it on connect if needed, rather than going through the current firmware update process.

This is a modified copy of hw_JoeyJr.py

[fredemmott]

openfpgaloader

The official way to get this on Windows is to use msys2 + pacman... not really viable IMO.

On the other hand, if i extract modretro's updater and grab openfpgaloader.exe from them:

.\openFPGALoader.exe --cable gwu2x --write-sram D:\chromatic_fpga\esp32t\impl\pnr\evt1_x2.fs
empty
write to ram
User requested: 6000000 real frequency is 6000000
Parse file Parse D:\chromatic_fpga\esp32t\impl\pnr\evt1_x2.fs:
Done
DONE
Load SRAM: [==================================================] 100.00%
Done
DONE

... that works

[Lesserkuma]

Oh thanks! I do not own this device and cannot test anything, so I am not comfortable adding it to the main repo for now. But great job nonetheless!

[fredemmott]

Thanks; for me to continue on this a bit more, is there any documentation on the commands and variables?

For example:

• DMG_FLASH_WRITE_BYTE appears to be largely equivalent to DMG_CART_WRITE, but pulsing the FLASH_WE_PIN
• It's going to be tough to figure out what WRITE_FLASH_CMD, FLASH_COMMAND_SET, FLASH_PULSE_RESET, FLASH_COMMANDS_BANK_1 etc all are meant to actually do

[fredemmott]

my notes on SET_FLASH_CMD:

SET_FLASH_CMD: 3 bytes
MBC3000v4: 1, 1 (UNBUFFERED), 1(WR)

BYTE 0:
  0. FLASH_COMMAND_SET_NONE (aka many vendors, just write, nothing special)
  1. AMD
  2. Intel
  3. Sharp: intel with a quirk
  Others: other vendors
BYTE 1: METHOD
  0. UNKNOWN - error?
  1. Unbuffered
  2. Buffered
  8. Paged
  Others: vendor
BYTE 2: FLASH_WE_PIN
  0. None
  1. WR
  2. Audio
  3. WR_RESET

[Lesserkuma]

My firmware module is planned to be released under GPL soon

[e0x70i]

Not sure how much it helps but have tested and confirmed the following work as expected with this fork:

• ROM and save dumps on ModRetro Tetris. Pokemon Pinball, and GameBoy Camera.
• Test writing ROM on ModRetro Tetris (wrote pokemon TCG rom).

[fredemmott]

I'm leaving this open for visibility that there is an option here, but this specific approach is now a dead end that won't get further development or testing.

I have a work-in-progress new approach, building on https://github.com/Lesserkuma/FlashGBX_LK_Firmware/ , and allowing playing + FlashGBX from the same firmware image.