| ??? 04/26/11 03:13 Read: times |
#182041 - The internal Watchdog Timer Responding to: ???'s previous message |
The problem with my 80C535 Development Board, which I will use as a simple 80C535 tester, is that it locks up after some minutes running. The reset circuitry is still use R-C timing.
I would like to replace the reset circuitry with the 3-pin MAX809 which has a precision Vcc monitoring, guaranteed Power On Reset pulse, and guaranteed Reset pulse at brown-out. I hope it can overcome the problem. If it can not, so I will consider using the internal watchdog timer that come with the 80C535. I will kick the dog at one to three important loops in the program, ( thanks Per, for your advice) and I will see the result. The dog sleeps at Power on or after an external reset, so we need to insert the instruction at the loop(s) : clr EN0.6 ; kick the dog clr EN1.6 ... ... elsewhere subsequently in the loop .... setb EN0.6 ; toggle setb EN1.6 .... Please anyone advice, and thank you very much for your attention. |
| Topic | Author | Date |
| Is 80C535 Compatible with 80C31? | 01/01/70 00:00 | |
| do not use pin numbers | 01/01/70 00:00 | |
| Supervisor Chip | 01/01/70 00:00 | |
| you say you want to test chips | 01/01/70 00:00 | |
| Reset Circuitry for 80C535 | 01/01/70 00:00 | |
| Timing | 01/01/70 00:00 | |
| probably because ... | 01/01/70 00:00 | |
| Supervisor/Watchdog Timer chip | 01/01/70 00:00 | |
| No timer needed to kick watchdog | 01/01/70 00:00 | |
| The internal Watchdog Timer | 01/01/70 00:00 | |
| good choice | 01/01/70 00:00 | |
| NE555 | 01/01/70 00:00 | |
| 8051 and 555 reset | 01/01/70 00:00 | |
| 555 Reset circuitry | 01/01/70 00:00 | |
| bad choice | 01/01/70 00:00 | |
| Reset Supervisor | 01/01/70 00:00 | |
| there are other possibilities | 01/01/70 00:00 | |
Other source | 01/01/70 00:00 | |
| did the datasheet not say so? | 01/01/70 00:00 | |
| It says so | 01/01/70 00:00 | |
| would it not be a good idea to do so before ... | 01/01/70 00:00 | |
| explain a bit about the nessecity of Supervisor Chip | 01/01/70 00:00 |