INS4004D in Pro-Log M900 PROM Programmer

Allison ajp166 at
Tue Aug 28 14:28:42 CDT 2007

>Subject: Re: INS4004D in Pro-Log M900 PROM Programmer
>   From: "Ethan Dicks" <ethan.dicks at>
>   Date: Tue, 28 Aug 2007 14:16:18 -0500
>     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at>
>On 8/27/07, dwight elvey <dkelvey at> wrote:
>>  From what I've seen in the spec sheets, one would just use
>> a slightly modified 2716 socket of any machine. A few lines
>> of code should be enough. No special voltages, just special
>> sequences. All easily handled in software.
>My recollection is that the 2716 needs something like 21V or 26V on
>the programming pin.  As for a modified socket, I have an old "Z-80
>Starter Kit" SBC that happens to have a built-in EPROM programmer on
>one of the three ROM sockets.  There's a toggle switch to disconnect
>the programming voltage, but once enabled, you simply write to the
>address range of that EPROM socket, and after the data are presented
>to the ROM, the circuit wiggles the programming pin to write the

It also requires the "write pulse" to be 50milliseconds long.  Write
is accomplished by supplying VPP (12, 21 or 26V version dependent)
then playing the OE/ and CE/ pins.


>It would not be difficult, in principle, to add this feature to, say,
>one of the empty ROM sockets on a PET, especially if you had an
>external benchtop power supply injecting the programming voltage
>(rather than generating it inside the PET housing).

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