ÜRP - Über Retro Programmer

An EEPROM programmer for retro playing.

• Can dump most parallel (EE)PROM memories, like 27xxx and 28xxx.
• Supports RW operations of most 28Cxxx EEPROM.
• Suppport may be extended to flash memories up to 1MiB.

What's inside

This repository is organized as follows

ÜRP
 |__ hw          --> KiCAD schematics
 |   |__ gerbers  -> fabrication files (gerbers)
 |   |__ urp.pdf  -> PDF schematic
 |   |__ urp.pro  -> KiCAD project
 |__ fw          --> source code for atmega 328
 |__ sw          --> source code for PC Command Line Interface
 |__ docs        --> files related to documentation

After clone, init submodules:

git submodule update

PCB Assembly

Designator	Description	Notes
C1-C5	capacitor ceramic 100n P5.08
C6-C7	capacitor ceramic 22p P2.54
R1	resistor 10k
R2-R4	resistor 330
Y1	crystal 16M
SW1	Tactile switch
D1-D3	LED 5mm	e.g. green, yellow, red
U1	microcontroller ATMega 328
U2 U3	shift register 74HC595
JP1-JP5	3-pin header 2.54	EEPROM size selection
J1	6-pin header 2.54
J2	ZIF socket 32 pin wide
J3	2-pin header 2.54	optional
R5	resistor 10k	optional
R6	resistor 3k3	optional
Q1	PMOS (2N7002)	optional

Warning: When Q1 is not mounted, JP7 must be shorted.

How to compile and load firmware

1. Mount atmega328 on an Arduino UNO board or equivalent. If is a fresh chip, you must load an Arduino compatible bootloader (e.g. optiboot).

2. Compile firmware in fw folder using the makefile. Change /dev/ttyXYZ123 with the correct serial port (e.g. /dev/ttyUSB0);

cd fw
make
make program AVRDUDEPORT=/dev/ttyXYZ123

1. Move the atmega328 on the ÜRP.

How to use EEPROM size selection pins

Jumpers JP1-JP6 must be placed according to memory size and technology. Each jumper has three positions, 1 (green), 2 (red) or unmounted (gray). Please refer to the following tables for correct placement.

EEPROM pinout

EPROM pinout

Notes:

• EPROM support is read only;
• Most EPROM have VPP on JP2. Datasheet recommends to put VPP=VCC during reading operations. I often keep JP2 in position (1) and make read operations starting from 32768 (A15=VCC).

How to compile CLI

cd sw
make

CLI options

Usage: ./serprog options

-r --read arg                read the content of eeprom in file. Must specify size and addr
-w --write arg               write the content of file in eeprom, then verify. Must specify addr
-v --verify arg              verify the content of the file with the eeprom. Must specify addr
-n --noverify                skip verification after write
-e --erase                   erase the eeprom (by software, i.e. write FF)
-V --verbose [arg]           set verbosity level to arg (0 low, 7 high)
-s --size arg                set reading size
-a --addr arg                set starting address (default 0)
-d --device arg              set serial device (default /dev/ttyUSB0)
-U --unlock                  unlock before
-P --lock                    lock after
-h --help                    print this help

Read a 28C256 EEPROM (8KiB)

./serprog --device /dev/ttyACMx --read dump.bin -s 8192

Write a binary image

./serprog --device /dev/ttyACMx --write dump.bin

If the EEPROM fails verify, SDP (Software Data Protection) may be on. Try disabling.

./serprog --device /dev/ttyACMx -U --write dump.bin

In both cases, size is deducted from the binary image.

Manually verify against a binary image

./serprog --device /dev/ttyACMx --verify dump.bin

Size is deducted from the binary image.

Protect EEPROM with SDP

./serprog --device /dev/ttyACMx -P