Description

The 2801Prog is a compact, low-cost programmer for the Motorola MCM2801P (2801) EEPROM and the NCR 52801 EEPROM.

The 2801 is a first-generation EEPROM requiring a high voltage (+25V) for programming and thus is not supported by commercial ‘universal’ programmers. However, it was widely used in its day and thus a reliable method of reading and programming it is required for the maintenance of legacy equipment.

For example, the 2801 is used to store the model differentiation and calibration data for the Mettler PE series of balances that are still widely used in laboratories around the world. As these chips age, the stored data is eventually lost and without it the scale will only display ‘ERROR’. While the data itself is widely available (see here for example) before the 2801Prog no commercial programmer supported the 2801 EEPROM and thus there was no easy way of fixing the balances. However, with the 2801Prog it is a simple matter of point-and-click.

The NCR 52801 EEPROM is a drop-in replacement for the MCM2801 which does not require a +25V supply. It is also not supported by ‘universal’ programmers but, due to being a drop-in replacement for the MCM2801 it can be programmed in the 2801Prog.

This programmer connects to any computer with a 9600 baud RS-232 port and a terminal emulator and allows reading, verifying, and programming of the 2801 EEPROM. Also, gEEProg, a Python application for Macintosh, Windows, and Linux is  available which allows access to all programmer functions via a GUI. The gEEProg application is available for download farther down this page.

Included:
1x 2801Prog Rev. 1 EEPROM Programmer
1x Power Adapter
1x DB-9 RS-232 Cable

Note:
Hard copies of the manual and software are not included – they can be downloaded at the links below
Download the 2801Prog Rev. 1 manual here
Download gEEProg and the gEEProg manual here
Download the MCM2801 datasheet here

Note 2:
After selling out of the original, Rev. 0, version of the 2801Prog, I have updated the board, ROM, and GUI application and am now selling a new Rev. 1 version. This new version features a ZIF socket on the side of the board instead of the middle which makes actuating the release lever much easier. It also fixes several small hardware and software bugs. The original Rev. 0 is obsolete and no longer available for sale, but its documentation, photos, and build files are preserved here for those who want them. Note also that the new gEEProg application replaces the 2801Prog GUI application that shipped with the Rev. 0 2801Prog. gEEprog works with all versions of the 2801Prog as well as all other D’Asaro Designs Programmers.

Note 3:
Starting with serial number 4 of the Rev. 1 boards, I updated the ROM (but not the hardware) so that the clock high level hold time would fully meet datasheet specifications. This change does not appear to have affected operation and I do not recommend upgrading unless you have some specific reason to, but the new ROM is compatible with all versions of the 2801Prog. The updated ROM is included with the complete product design available at the bottom of this page.

Download the schematic, PCB layout, parts list, and source code for this product here. Note that these files are available for PERSONAL, NON-COMMERCIAL USE ONLY. In short, you are welcome to use them to build this product yourself, but you must contact me to work out a commission if you wish to sell anything derived from them. This product was designed in ExpressPCB so you will need to download a copy of that software from expresspcb.com before you can view the files. Also, MPLABX (available from microchip.com) will be useful when opening the project file containing the source code.