Does anyone know what the pin configurations are for the HP-85 ROMS? Is there any documentation to describe how the HP-85 communicates with the ROM modules? It would be an interesting project to develop a "programmable ROM drawer" but possibly hold many ROM images like the MLDL2000 or clonix. Please let me know if you have ever seen documentation for such or have successfully built one.
HP-85 ROM Pin Configurations
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10-13-2004, 07:41 PM
10-14-2004, 04:56 AM
The circuit diagrams of the HP-85 are included in the service manual of the HP-85 in the MoHPC CDROM collection. Here are the option ROM pinouts:
___________________ Note that the logic is 6V and the clocks are 12V !!! The ROM pinouts are all the same, the ROM socket pins are also all the same. Each ROM selects itself if it sees its id . This is the reason that if you plug two (say) I/O ROMS, you may damage your HP-85. **vp
10-16-2004, 10:13 PM
Would the 2708 EPROM work? It has the 12V, -5V but it only has a +5v. The spec states that that it would accept 5.25v max. Do you know of an EPROM that would compare to this HP-85 specification?
10-16-2004, 11:44 PM
JeffD wrote:
Sorry, the HP ROMs have a lot of logic built into them.
Alternatively you may use a programmable ROM drawer http://www.series80.org/Manuals/HP82929A.pdf Unfortunately they are rather rare and fetch a high price on eBay (latest one went for $159.25, http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5128991233) |
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