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Message

3.3V 68LK332 reset problems

2002-10-31 by Allen Nance

Hello Group:

	I have a new design with the 3.3V 68LK332 part. I have not used the 3.3V
part before but have used the 68332 extensively. The problems I am having 
are at power up.

1. When I apply power the part comes up most of the time. (80%)

2. When I add a power-up reset chip MAX690, the part never resets correctly.
      The '332 is reset cycling about every 12.5 msecs.
      The CLKOUT pin is at about 10Mhz (I use at 40kHz crystal)
      At reset the CSBOOT is accessing ROM with a pulse width of 200nsec 
for about
       60 cycles and then quits.
       The MAX690 is pulling RESET low about every second for about 200msecs
       (this is the MAX690 watchdog timeout)

3. I read a while back about decreasing the size of the series resistor for
3.3V applications, so I tried that but still no luck.

I am puzzled why it would come up OK with a straight power up but not
with a power-up reset monitor.

Any thoughts out there?

Allen Nance

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