Adapter to read Wms Decoder PROMs (7641)

DarrenF

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I've been meaning to make up an adapter to try reading my Williams decoder PROMs (like the ones on Stargate, Joust, Robotron, etc. boards). I was waiting until I had enough on my list to order some 24-pin sockets, until I realized I had a pile of 40-pin sockets... duh.

So attached is a pic of the adapter I made for my GQ-4X. I read it as a 2716. Of course, I end up with the data 4x, as the 7641 is only 512 bytes and a 2716 is 2048 bytes.

To build one, just use 2 sockets; bend out pins 18 & 19 and tie to Vcc thru a 4.7K (or anything in the ballpark, it's just a pull-up); bend up pin 21 and tie to GND. Read as 2716.

To verify the data, I just took the "correct" decoder images and copied them over 4 times to make a repeated version, and used it to "verify". (copy /b file1+file1+file1+file1 file1x4)
 

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  • 7641_adapter.jpg
    7641_adapter.jpg
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Here's a board I made for it. It adapts it to 2716. You can have this made with oshpark or you can build what the individual did above.

To reiterate what was said above. 2716s are 2kbyte where as 82S141 is 512 byte. Meaning that this will be duplicated 4 times. The easiest way to trim it is to copy it into a binary editor like HxD and delete everything after 1FF and then save.
 

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  • 82S141_dumper.zip
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Can you add an entry that would read the right length if you defined it in the devices file?? That could avoid the 4 times issue.

From the GQ4x4 manual:
The devices.txt file is the main supported device list configuration file. It is located in the application's directory. Advanced users may change it or add new devices to it. The file format is text format and it can be opened and edited by any text editor. Each device has to be defined with one text entry, which can span several lines. The following device attributes can be defined individually: Name="Device Name", ID="Device ID in Hexadecimal", Class="Class Name", Category="Category Type", MFG="MFG Name", Speed="Default Speed", Package="Package", Adapter="Adapter", CodeSize="Code Size", EepromSize="Eeprom Size", DIP="DIP Setting", VCC="Vcc", WVPP="Write Vpp", WVCC="Write Vcc", BVCC="Blank Vcc", RVPP="Read Vpp", Message="Text to be displayed to the user about switch settings, adapters, etc";
 
Where is @DarrenF these days?
@dogdayaft if you want the easy way just buy a replacement from @steph

There are many ways to read and verify these including a programmer that reads 82s141s or signature analysis.
 
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