The purpose of emurom is to make it fast and convenient to hack code in ROMs without having to repeatedly remove and reprogram an actual ROM chip.
Emurom is a board which connects through USB to a host computer, and can be connected in place of a parallel ROM chip on a target device. It acts as a ROM chip, but holds its data in a static RAM, which can be updated at any time through the USB connection. Optionally it can provide power (5v) to the device by shorting a jumper, and it also has a lead to clip to the reset signal of the target device, to automatically reboot it when a new ROM image is uploaded.
Hardware design (kicad project) is in the root directory. The firmware for the
microcontroller is located under fw, while in the emurom subdirectory, there
is a UNIX program which can be used to upload a ROM image to the device, simply
by running it with the name of the ROM image as a command line argument.
- Project website: http://nuclear.mutantstargoat.com/hw/emurom
- Git repository: https://github.com/jtsiomb/emurom
- Schematic (PDF): http://nuclear.mutantstargoat.com/hw/emurom/emurom-schematic.pdf
Copyright (C) 2020 John Tsiombikas nuclear@member.fsf.org
All hardware designs in this project are free/open hardware. Feel free to
manufacture, sell, use, modify and/or redistribute, under the terms of the
Creative Commons Attribution Share-Alike license (CC BY-SA). See LICENSE.hw
for details.
All software in this project (firmware and host upload program) are free
software. Feel free to use, modify and/or redistribute under the terms of the
GNU General Public License version 3, or at your option any later version
published by the Free Software foundation. See LICENSE.sw for details.
This git repository contains the current project files and source code for emurom, but it does not include any binaries or build products.
The release archive includes the schematic PDF, gerber files for PCB manufacturing, datasheets, and pre-built binaries (firmware image and host program).
Latest release (emurom rev2):
- emurom website: http://nuclear.mutantstargoat.com/hw/emurom/release/emurom-rev2.tar.gz
- github mirror: https://github.com/jtsiomb/emurom/releases/download/v2/emurom-rev2.tar.gz
Emurom rev2 BOM:
| # | name | description | package |
|---|---|---|---|
| 1 | U1 | ATmega328P AVR microcontroller | TQFP 32 |
| 1 | U2 | MCP2221 USB-serial converter | SOIC 14 |
| 1 | U3 | 74HCT157 quad 2-1 multiplexer | SOIC 16 |
| 2 | U4,U5 | 74HCT595 8-bit shift register w/3-state output | SOIC 16 |
| 1 | U6 | UM61512AK 64k static RAM (or similar 64k SRAMs) | PDIP 32 |
| 3 | U7-U9 | 74HCT244 octal 3-state buffer | SOIC 20 |
| 2 | C1,C2 | 22 pF ceramic capacitor | 0805 |
| 11 | C3-C13 | 0.1 uF ceramic capacitor | 0805 |
| 2 | R1,R2 | 330 Ohm resistor | 0805 |
| 6 | R3-R8 | 4.7 kOhm resistor | 0805 |
| 2 | D1,D2 | LED | 0805 |
| 2 | D3,D4 | 1N4148 signal diodes | 0805 |
| 1 | Y1 | 14.7456 quartz crystal | 7.6x4.1mm SMD |
| 3 | JP1-JP3 | 2-pin male header (jumper pins) | |
| 1 | J1 | 6-pin (2x3) male header or IDC conn. 2.54mm pitch | |
| 1 | J2 | molex 105017-1001 micro-USB (type B) connector | |
| 1 | U10,J3 | 24-pin (2x12) male header or IDC conn. 2.54mm pitch | |
| 1 | U11,J5 | 28-pin (2x14) male header or IDC conn. 2.54mm pitch | |
| 1 | J7 | 1-pin male header |