| ??? 01/24/05 16:41 Read: times |
#85670 - Why Responding to: ???'s previous message |
Erik Malund said:
Why the 13 bit kluge? TL1 is not affected. Erik I don't know why it was designed as 13 bits - better ask Intel. However, I need an accurate time. Using timer0 in 8 bit auto reload mode gives accurate timing but does not give a long enough interval. 16 bit mode does not have auto reload so, if I used this mode, by the time I have reloaded the timer in an ISR the actual interval is uncertain. *IF* the prescaler in mode 0 is unaffected by reloading the top 8 bits (TH0), then *provided* I do the reload before the prescaler overflows and starts incrementing TH0 again then my timing will be accurate and jitter free. There is no mention in the data books about what happens to the prescaler so I *assume* it is unaffected but I need to know for sure. I don't want to use timer2 which has a 16 bit autoreload because a) this code may be used on a very low end 8051 without timer2 and b) timer2 will be needed for baud rate generation. Ian |
| Topic | Author | Date |
| Timer 0 Mode 0 | 01/01/70 00:00 | |
| no and why | 01/01/70 00:00 | |
| CD quality sampling freq.? | 01/01/70 00:00 | |
| oops | 01/01/70 00:00 | |
| Why | 01/01/70 00:00 | |
| alternatives | 01/01/70 00:00 | |
| Alternatives | 01/01/70 00:00 | |
| comment | 01/01/70 00:00 | |
| 16 vs 13 | 01/01/70 00:00 | |
| Why not T2 | 01/01/70 00:00 | |
| uC crystal ? | 01/01/70 00:00 | |
| uC Crystal | 01/01/70 00:00 | |
| cost saving because of may | 01/01/70 00:00 | |
| Cost Saving | 01/01/70 00:00 | |
| at those volumes | 01/01/70 00:00 | |
| baudrates | 01/01/70 00:00 | |
Baud Rates | 01/01/70 00:00 |