| ??? 01/09/12 18:41 Modified: 01/09/12 19:43 Read: times |
#185396 - Use Timer2 since a S52 has a timer2 Responding to: ???'s previous message |
From the bible:
RCAP2 = 65536 - F_CPU / 32 / 31250 this is 65525 for 11.059MHz i.e. 31418 baud Incidentally, now that I have had a play, I see that you can do the sum very easily. e.g. 7.3728MHz -> RCAP2 = 65536 - 7 -> 7.3728/7 = +5.3% 11.059MHz -> RCAP2 = 65536 - 11 -> 11.059/11 = +0.54% 14.7456MHz -> RCAP2 = 65536 - 15 -> 14.7456/15 = -1.7% 18.432MHz -> RCAP2 = 65536 - 18 -> 18.432/18 = +2.4%% UARTs need to be within +-2% of your desired baud rate. I would be quite happy with 0.5%. It looks as if 11.059 is your only viable choice. 14.74Mhz should just work. I am sure there are some tables somewhere. I just got the calculator out. Anyway, why are you worrying about the F_CPU? You simply choose the best crystal for your critical peripherals. Then scale all your non-hardware calculations. David. |
| Topic | Author | Date |
| 31.25K Baud Rate w/Crystals Other Than 6, 12 or 24MHz | 01/01/70 00:00 | |
| Use Timer2 since a S52 has a timer2 | 01/01/70 00:00 | |
| Timer2 Baud Rate | 01/01/70 00:00 | |
| Your maths look fine | 01/01/70 00:00 | |
| I just got the calculator out | 01/01/70 00:00 | |
It Works!!! | 01/01/70 00:00 |