| ??? 02/14/05 22:22 Read: times |
#87441 - because Responding to: ???'s previous message |
Sorry that I am so stupid, but I don't understand why wouldn't the timer method catch a 0-1 transition during an ISR?
The timer roll over, causing an interrupt. Till the timer is again set to ffff and reenabled no rollover, and thus no interrupt will happen. I have seen the "timer external interrupt" applied several times, not for slope, but to get one more interrupt and, in one case, it proved necessary to interchange two interrupts (timer and "regular" external) because the one at the timer occasionally repeated very fast. Anyhow a much better "external timer interrupt" is to use an up/down timer and, as the first instruction in the ISR reversese the direction. That cut the lag to next to nothing. Of course, here again we need a modern derivative. And I don't believe that somebody with the former background would come and ask such question here The sad fact is that many that have started under the premises you advocate, never get away from them, the habits get totally ingrained. I have the experience that if someone uses "small" as an excuse to do less than optimum, then that person will never get in the habit of reaching for optimum. Anyhow, I have no problem that any hobbyist use a "wrong" processor, just please do not ask me to say it is right. Erik |
| Topic | Author | Date |
| Ext Interrupt - Transition Activated | 01/01/70 00:00 | |
| Turn a falling edge into a rising edge? | 01/01/70 00:00 | |
| Did you read the | 01/01/70 00:00 | |
| both interrupts possible | 01/01/70 00:00 | |
| I use this | 01/01/70 00:00 | |
| I use PCA | 01/01/70 00:00 | |
| not on AT89C2051 ! | 01/01/70 00:00 | |
| who forces him | 01/01/70 00:00 | |
| Who forces? The circumstances. | 01/01/70 00:00 | |
| New Zealand | 01/01/70 00:00 | |
| Yes, the perspective! | 01/01/70 00:00 | |
| because | 01/01/70 00:00 | |
| I also use AT89C51RC2 | 01/01/70 00:00 | |
| little boy | 01/01/70 00:00 | |
| That's why not | 01/01/70 00:00 | |
glady | 01/01/70 00:00 | |
| Don't underestimate the good old USA | 01/01/70 00:00 | |
| two views | 01/01/70 00:00 | |
| Two academic questions | 01/01/70 00:00 | |
| suggestions | 01/01/70 00:00 | |
| Transition reversed from the bible | 01/01/70 00:00 | |
| language | 01/01/70 00:00 | |
| clarification on the language | 01/01/70 00:00 | |
| something smells | 01/01/70 00:00 | |
| Defective Chip | 01/01/70 00:00 | |
| we have all been there | 01/01/70 00:00 | |
| OK - I'll have a sleep | 01/01/70 00:00 | |
| glitchy? | 01/01/70 00:00 |