| ??? 01/16/13 19:38 Read: times |
#189197 - Some things to check... Responding to: ???'s previous message |
Koen De Ganck said:
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 Check the ALE pin, that can show what mode the device started in, and when it exits reset. Is this only on a cold start ? If you do a small brownout, just enough to trigger the LM810, or a manual reset, is that always OK ? Can you add a first line of code that flips an unused pin, on reset, so you can check if the issue is really reset. I have noticed the Reset Hyst of the LP51's is on the low side, but that is only seen on external RST drive with slow edges. The POL Pin is a simple EXOR with the RST pin, so is unlikely to do anything magical. Do you use the Xtal signals for anything ? |
| 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 |