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Koen De Ganck
01/17/13 14:06
Read: 913 times
Lede
Belgium


 
#189238 - loads on PSEN
Responding to: Jim Granville's previous message
The load on PSEN is an input of a GAL 16V8, it is an old design, in fact PSEN is not needed any more.

The bad start-up effect is a 'capacitive' transient.
The board normally starts up and runs for many years, but at least it should start-up without problems.

The RST is driven by the µC, so in fact there is still a clean reset without LM810. The inverter on RST resets other devices ( HC259,...)

PSEN has no meaning on a 64KB device, could be used as an I/O (extra pin on Port 4).


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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