| ??? 01/17/13 21:06 Read: times |
#189238 - loads on PSEN Responding to: ???'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). |
| 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 |