Hallo William, > A logic probe would be safer. You would not be able to measure the > voltage, but you should be able to tell which is the program pin. What good is to know which pin is the program pin if you don't know where to apply the 25 V to? We have 24 pins: 1- 13 addresslines 2- 8 datalines 3- Vss = GND 4- Vcc 5- ChipSelect We can scratch 1 to 3 as possible candidates for the 25 V. Choosing pin 24 = Vcc for the 25 V means the 68764 needs an internal 5V regulator for supplying power to the rest of the IC not able to cope with the 25 V. Think of the heat generated using this construction. I favour the CS-pin, both as Vpp and program pin: apply 25 V the moment the address and data is valid. This also would mean that, when using an ordinary voltmeter, we would not measure 25 V but maybe something like 10 V. Using a scope would be better in this case. > A logic probe would be safer. Yes, for the EPROM and the prommer. But can the probe handle 25 V? :) ___ / __|__ / / |_/ Groetjes, Ruud \ \__|_\ \___| http://Ruud.C64.org Message was sent through the cbm-hackers mailing list
Archive generated by hypermail 2.1.1.