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Jim Granville
01/17/13 13:06
Read: 807 times


 
#189233 - small capacitor ?
Responding to: Koen De Ganck's previous message
Koen De Ganck said:

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 )


Can you define 'small capacitor', and was that applied to PSEN ?
To GND, or Vcc ?
Was the '810 reset active still ?
I measured a normal PSEN pin, source -27uA @ 5V


List of 24 messages in thread
TopicAuthorDate
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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