| ??? 01/16/13 09:42 Read: times |
#189185 - Reset issue with new Atmel AT89LP51ED2 |
Dear,
I'm having issues with the reset of this new chip from Atmel on an existing board. The same board has been working fine with a P89C51RD2 since many years. The new controller does not always start-up well. Even a extra reset pulse does not make it start. I'm in contact with Atmel and they seem to do some tests, but can not reproduce the problem. I've done many test with different board and power supplies ( rise time, voltage, start-up behaviour ). The Philips (NXP) chip always starts, but the other fails more than 50%. The external reset chip is LM810 (push-pull), with series resistor of 3K3 ( reset > 200ms), 1 extra HC port load After power-up the external oscillator is 20Mc is running Vcc = 5V I have 3 different batches with the same issue. It looks as if something is lockup ? Does somebody recognize this problem, maybe has solved it or has some idea's ? Thanks for your answer or advice. Koen |
| Topic | Author | Date |
| Reset issue with new Atmel AT89LP51ED2 | 01/01/70 00:00 | |
| Do never use a µC from which only a preliminary... | 01/01/70 00:00 | |
| configuration settings | 01/01/70 00:00 | |
| what about negative reset? | 01/01/70 00:00 | |
| good idea but | 01/01/70 00:00 | |
| Some things to check... | 01/01/70 00:00 | |
| also try no LM810 at all | 01/01/70 00:00 | |
| reset is inverted | 01/01/70 00:00 | |
| no strange signals | 01/01/70 00:00 | |
| Extra modes ? | 01/01/70 00:00 | |
| pull-up on PSEN solves the problem | 01/01/70 00:00 | |
| small capacitor ? | 01/01/70 00:00 | |
| small capacitor | 01/01/70 00:00 | |
| side-stepping the problem? | 01/01/70 00:00 | |
| SST could be an option | 01/01/70 00:00 | |
| final status AT89LP51ED2 reset | 01/01/70 00:00 | |
| Clarifies | 01/01/70 00:00 | |
| loads on PSEN | 01/01/70 00:00 | |
| An isolated PSEN works fine ? | 01/01/70 00:00 | |
| GAL causes problem | 01/01/70 00:00 | |
| ATF16V8CZ has Pin-keeper | 01/01/70 00:00 | |
| 'Z' indeed | 01/01/70 00:00 | |
| ATF16V8BQL has Icc of ~1.5mA | 01/01/70 00:00 | |
'BQL' version could be an option | 01/01/70 00:00 |