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Koen De Ganck
01/17/13 03:01
Read: 934 times

#189218 - pull-up on PSEN solves the problem
Responding to: Jim Granville's previous message
re-reset : only works if the first one succeeded. If it fails even a hardware reset does not work after the supply has stabilized

PSEN : is loaded with 1 port, the traces are within 2 x 3cm (4 endpoints ) on a multilayer.
OCD is disabled

I put a pull-up of 100K on PSEN and it seems to be the solution.
A higher value (1M ) should also work ( RC < 100µs )
Maybe the Atmel ship is more sensitive than the NXP version.
Adding a small capacitor on a chip that resets well, make it 'fail' ( startup in bootloader )

As the first samples I got did not have a working bootloader, I bought a programmer (ASIX Presto) and did all programming with it. I also wrote an IAP program to upgrade firmware.

The docs and info on the Atmel website is still not updated, even not clear and disturbing, but I can go on now with the tools and info I have.

Thanks Jim for asking me the right questions and giving the right hints
Thanks to Kai, Jan for responding.

List of 24 messages in thread
Reset issue with new Atmel AT89LP51ED2      Koen De Ganck      01/16/13 02:42      
   Do never use a µC from which only a preliminary...      Kai Klaas      01/16/13 05:48      
      configuration settings      Koen De Ganck      01/16/13 05:59      
         what about negative reset?      Jan Waclawek      01/16/13 06:56      
            good idea but      Koen De Ganck      01/16/13 07:23      
   Some things to check...      Jim Granville      01/16/13 12:38      
      also try no LM810 at all      Jim Granville      01/16/13 13:02      
         reset is inverted      Koen De Ganck      01/16/13 13:30      
      no strange signals      Koen De Ganck      01/16/13 13:18      
         Extra modes ?      Jim Granville      01/16/13 16:30      
            pull-up on PSEN solves the problem      Koen De Ganck      01/17/13 03:01      
               small capacitor ?      Jim Granville      01/17/13 13:06      
                  small capacitor      Koen De Ganck      01/17/13 14:10      
   side-stepping the problem?      Jan Waclawek      01/17/13 01:34      
      SST could be an option      Koen De Ganck      01/17/13 03:08      
   final status AT89LP51ED2 reset      Koen De Ganck      01/17/13 07:43      
      Clarifies       Jim Granville      01/17/13 12:59      
         loads on PSEN      Koen De Ganck      01/17/13 14:06      
            An isolated PSEN works fine ?      Jim Granville      01/17/13 14:30      
               GAL causes problem      Koen De Ganck      01/17/13 15:41      
                  ATF16V8CZ has Pin-keeper      Jim Granville      01/17/13 16:02      
                     'Z' indeed      Koen De Ganck      01/17/13 16:35      
                        ATF16V8BQL has Icc of ~1.5mA      Jim Granville      01/17/13 16:54      
                           'BQL' version could be an option      Koen De Ganck      01/17/13 17:50      

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