When I try to validate (green SUM button on the CRC32/SHA1/etc. libraries)
40 or 42 pin EPROM's. I receive "no signature found" or "no match found".
What is the difference between the S4 1640 and S4 4042?
What is MROM/JEDEC?
If your are using 16-bit EPROM's (40 or 42 pin EPROM's) please make sure that you
are using the proper adapter.
There are two formats for those chips which are incompatible: JEDEC and MROM. Please
see the diagrams below. The Pins in red are data lines. Please note that the JEDEC
format has the data lines on the left. Whereas with the MROM format they are located
at the bottom.
The JEDEC format is 40 pins. The special MROM format can be either 40 or 42 pins.
Please see the MROM diagrams below.
Then the 42-pin version.
Consequently there are 2 modules for the S4. The Mod40 Dataman part number "S4 1640"
which uses the JEDEC format. Then the Mod42 part number "S4 4042" which uses the
MROM format pin-out format.
How can I tell which format or which adapter I need to use?
Any 42 pin EPROM is in the MROM format. If your EPROM is 40 pins you will
need to consult our list to find out the format.
16 Bit Modules
You will need to know the part number of your chip which may require you to remove
a label on the top of the chip.
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