[Coco] Programming a 68766 EPROM

[Warren Hoslet]

>The 27xx series of chips with the exception  of the 2716 requires 12.5 
>volts for
>Vpp. The MCM68766 requires 25 Volts.  Be sure your progrmmer is setup to s
>upply that much voltage. Also to program the 68766 you need to bring the 
>enable
>upto 5 Volts then put the data and address to the chip then raise the 
>enable
>voltage to 25 volts.
>
>james
>
-
I did manage to get the Willem programmer to READ a 24-pin CoCo ROM, but it 
looks like programming a 68766 will not be possible. As you stated James, 
the G/Vpp input on the 68766 needs to be placed at 5V during data and 
address setup, then pulsed at 25V to write. The Willem requires the EPROM to 
have two control lines for programming: Vpp held at a constant voltage, and 
another line which accepts the Write pulses.

I guess if I really want to do this I'll have to spend the bucks to get a 
Transtronics Pocket Programmer. :(