Programming CMT EPROM modules for HP-41



#2

I have succeeded in programming one of the subject modules and it turns out it is pretty straight forward. The pads that the PLCC package EPROM are soldered down to, are actually vias that go through the board to corresponding pads on the under side and all that is required to program them is to make connections from these pads to a standard EPROM programmer. I made up a connector using pogo pins that have their sockets anchored between two layers of 0.05" pitch perfboard that I got from Digi-Key. I mapped the contacts to a "standard" 28 pin dip connector and was able to read and program the EPROM using my ancient Xeltek Superpro II. There may be problems with some programmers because there are resistors on the module that pull down the CE and OE pins so when powered on all the outputs are active and at least one of my EPROM programmers did not like this.

One thing to watch out for is it would seem that the commonly available images of ROM modules the 10 bit HP41 words are split into two byte with the byte containing the 2 MSB first and then the next byte contains the lower 8 bits, this is the opposite of how the CMT modules want the data arranged, they want the lower 8 bits first. I reversed the bytes by splitting the image, writing alternate bytes to two files and then merging the two files to get the correct byte order.


#3

Hello, I'm interested as I have one 16K CMT module that is currently unused, it just contains the CMTTST program.
Running CMTTST with module plugged in port 3 gives:

BANK 0 TEST
BANK 1 TEST
BANK 2 TEST
BANK 3 TEST
16K PT3 OK

Would you consider providing programming services for these modules? Or can you share more details about your hardware design?

Edited: 21 Jan 2013, 4:26 a.m.


#4

I could provide programming service for a small fee, but I will also post my design once I decide on a good way to align the module and hold it against the pogo pins.


#5

Hi,

this is how the original CMT EPROM adapter looks like.

HTH

Ray

Edited: 22 Jan 2013, 5:47 p.m.


#6

Thanks for the pictures that is much clearer all I had seen before was tiny pictures, unfortunately I don't think I can reproduce the clamping mechanism they used.


Possibly Related Threads...
Thread Author Replies Views Last Post
  HP-41(CL): The easiest way to transfer FOCAL programs from a Linux PC to the HP-41 Geir Isene 13 766 12-05-2013, 02:40 AM
Last Post: Hans Brueggemann
  HP 41 Advanced Programming Tips Michael Fehlhammer 0 150 11-28-2013, 06:11 PM
Last Post: Michael Fehlhammer
  HP Prime - Short "learning" modules CR Haeger 1 176 11-27-2013, 02:13 PM
Last Post: Jonathan Cameron
  Library#4 Modules mass-update and New Overlays Ángel Martin 0 207 11-09-2013, 05:55 AM
Last Post: 'Angel Martin
  hp41cv memory modules tim peterson 10 494 11-07-2013, 11:09 PM
Last Post: Garth Wilson
  Best way to test HP-71B RAM modules (the 32K/96K ones etc.)? Philippe Lasnier 4 390 09-25-2013, 09:54 AM
Last Post: Philippe Lasnier
  HP-41 New versions of your favorite modules - with an AOS twist :-) Ángel Martin 13 541 06-21-2013, 01:29 PM
Last Post: Diego Diaz
  shelf life time of a ROM, EEPROM, EPROM vs Mask Rom Guido (Canada) 6 375 01-11-2013, 04:09 PM
Last Post: Thomas Falk
  Question about X modules for HP41x Ignacio Sánchez 7 383 12-13-2012, 07:00 AM
Last Post: Geoff Quickfall
  Series 80 EPROM cards Paul Berger (Canada) 0 146 12-08-2012, 07:50 PM
Last Post: Paul Berger (Canada)

Forum Jump: