Print Page - 89C668H overprogram

Title: 89C668H overprogram
Post by: microappl on March 14, 2004, 02:50:21 PM

I designed a product using 89C668H.
I find a programming yield problem using FM 1.84.
On about 20% of the 668's the chip will jump to a random location and crash while executing the main idle loop.
The failing chip(s) verifie(s) under FM.

If I overprogram the failing chip without erasing it two or three times, this seems to solve the problem.

This would seem to indicate that the 668 ISP programming code has a problem.

Title: Re: 89C668H overprogram
Post by: erik malund on March 15, 2004, 05:31:19 AM

just a guess. Do you have P2.7 AND P2.6 helke high

Erik

Title: Re: 89C668H overprogram
Post by: Andy Ayre on March 15, 2004, 08:43:08 AM

Sounds like an electrical problem. Do you have gitches or ripple on the power supply or RST pin? What about the XTAL pins? What is the voltage actually at the VCC, GND and RST pins? Does the signal at the XTAL pins look ok?

Title: Re: 89C668H overprogram
Post by: erik malund on March 15, 2004, 11:49:27 AM

Do you have Vpp directly to +5?

Erik

Title: Re: 89C668H overprogram
Post by: udj on March 19, 2004, 08:02:40 AM

I am using 89C668H. product
I find a programming problem flash programming.
Chip is responding fro ISP communication what will be the problem

This would seem to indicate that the 668 ISP programming code has a problem.

Title: Re: 89C668H overprogram
Post by: Andy Ayre on March 19, 2004, 08:18:55 AM

Can you elaborate on "Chip is responding fro ISP communication what will be the problem"? What are you observing?

Did you let P2.6 and P2.7 float or pull them high?

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Archive => Old Topics => Topic started by: microappl on March 14, 2004, 02:50:21 PM