| ??? 07/26/05 12:45 Read: times |
#98150 - that was not 8255 Responding to: ???'s previous message |
Steve M. Taylor said:
In the same way, the fastest modern PC is still "based on the 82C55", because thats how the original PC speaker was driven. That was 8253 (timer). I think there was no 8255 in the PC. Speaking of 8253, the first time I was burnt by the this-PC-is-not-PC syndrome was, when I tried to make a finer timing on PC by reading the timer's (which is still - even today - a kind of a 8253 implemented somewhere inside the chipset) registers. It worked fine on my PC (and many more), and I went happily with the program into production, until one day a complaint from field came (works intermittently). The outcome of a lengthy experimenting was, that reading the timer registers on this particular chipset sometimes (1-in-1000 or so) gave an erratic highest bit... Jan Waclawek |
| Topic | Author | Date |
| 8255 interfacing problem | 01/01/70 00:00 | |
| well.. | 01/01/70 00:00 | |
| 8255 interface problem | 01/01/70 00:00 | |
| If you must use 8255 | 01/01/70 00:00 | |
| My datasheet says..... | 01/01/70 00:00 | |
| Settle Erik! | 01/01/70 00:00 | |
| 8255 problem | 01/01/70 00:00 | |
| hardware | 01/01/70 00:00 | |
| adding to Steve.. | 01/01/70 00:00 | |
| Comment | 01/01/70 00:00 | |
| Relic | 01/01/70 00:00 | |
| that was not 8255 | 01/01/70 00:00 | |
| Actually.... | 01/01/70 00:00 | |
| ot: 825x in PC | 01/01/70 00:00 | |
| Parallel port | 01/01/70 00:00 | |
| NOoooooooooooooooooooo | 01/01/70 00:00 | |
| Ooops | 01/01/70 00:00 | |
| OK I give it up! :-) | 01/01/70 00:00 | |
| Just like | 01/01/70 00:00 | |
| 8255 in original PC | 01/01/70 00:00 | |
| If I did not keep up with the times and | 01/01/70 00:00 | |
| Do your kids drive Segway? | 01/01/70 00:00 | |
| the real problem is not that the 82xx is | 01/01/70 00:00 | |
| Erik - A history lesson | 01/01/70 00:00 | |
| ok, even further back | 01/01/70 00:00 | |
| Picky, picky | 01/01/70 00:00 | |
| are we getting there now? | 01/01/70 00:00 | |
Oh altight then :-) | 01/01/70 00:00 | |
| More info needed | 01/01/70 00:00 | |
| Pull up resistors. | 01/01/70 00:00 | |
| Pullups | 01/01/70 00:00 | |
| no can do | 01/01/70 00:00 | |
| Yes he can! | 01/01/70 00:00 | |
| does not make it current | 01/01/70 00:00 | |
| my opinion... | 01/01/70 00:00 | |
| did you not read | 01/01/70 00:00 | |
| Nope | 01/01/70 00:00 | |
| 8255 PROBLEM | 01/01/70 00:00 | |
| 10 Points | 01/01/70 00:00 |