I found my problems I have had for the past 12 hours of programming the (ST)M27C801 eproms. I placed the chip in the zif to program. I started the programming process and then measured the voltage across pin 24 of eprom and ground and I was only getting 12.25V These chips have to have 12.7V to program. So what I did was soldered a small wire from pin 14 on the LM324 by the green and red led and took a normal 32 pin socket and bent up pin 24 on the socket and soldered the small wire from pin 14 on the chip to pin 24 on the 32 pin socket. Inserted the socket in the zif and then inserted the eprom in the socket and programmed just fine!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! It's a shame I didn't catch that before I ordered 2 more programmers. But that's ok. I can never have enough programmers. As far as the jumper setting, set them like it shows in the pictures and it should work. I hope this helps for ANYBODY!
Hey ZLM, Do you know why I am only getting 12.25V across pin 24? Would it be safe to try the 15V considering they need 12.7v? That would only be 2.3V more than normal. Speaking of normal, Does anyone know what they are getting(in voltage) across pin 24 of zif?
Hey ZLM, Do you know why I am only getting 12.25V across pin 24?
Check the voltages on the step-up regulator. You can increase VPP by changing resistor values.
quote:Would it be safe to try the 15V considering they need 12.7v? That would only be 2.3V more than normal.
No. VPP(abs max) for M27C801 is 14V. Since VPP is the highest voltage the device allows, exceeding the absolute max is the easiest way to damage the part. When they say 12.75V +/- 0.25V, they usually mean it.
quote:Speaking of normal, Does anyone know what they are getting(in voltage) across pin 24 of zif?
Depends on your programmer. I get 12.6V because that's what my resistor values are supposed to give (Willem 4.1).
Programming the 27c801 eproms!!!!!!!!!!!!!!!!!!!!!
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Posted - 04/02/2006 : 00:02:39
