??? 12/10/10 03:14 Read: times |
#180045 - problem with watchdog of 8253 |
Friends,
I am sorry, if this is this is a repeat question, but I seek help for this issue. I am using Atmel's AT89S8253 extensively. Recently I have come across this problem. Present project uses 11.0592 xtal. The system continuously communicates on 232 @2400bps. It works perfectly well with watchdog disabled, with or without 22pf xtal caps. The problem starts, the moment, I enable watchdog; the oscillator starts at wrong frequency. I havr not measured freq., but buzzer-beeps are longer, and it stops communicating on 232. The watchdog is loaded at power as begin: mov sp,#stacks orl eecon,#03 call stlwd mov ie,#92h ;t0,serial enabled ...program follows...... stlwd: mov wdtcon,#0a4h lwd: mov wdtrst,#01eh mov wdtrst,#0e1h ret Timer0 designed to be 8bit auto-start for 76800Hz, watchdog I am recalling at 2.5msec with help of counter. Have a Great Time, Always. Thanking you, |
Topic | Author | Date |
problem with watchdog of 8253 | 01/01/70 00:00 | |
oscillator starts at wrong frequency? | 01/01/70 00:00 | |
Watchdog rate? | 01/01/70 00:00 | |
example | 01/01/70 00:00 | |
How to post formatted source code | 01/01/70 00:00 | |
Not a good way to handle a watchdog! | 01/01/70 00:00 | |
If I recall | 01/01/70 00:00 | |
Avoid the AT89S8253... | 01/01/70 00:00 |