| ??? 03/21/06 16:47 Read: times |
#112718 - reread the "bible" Responding to: ???'s previous message |
There is also a tutorial here, click on the left.
The traditional '51 IO pin is quasi-bidirectional, in other words, it's output is open collector (well, it's MOS so it's open drain rather). If you write 1 onto it from inside, the transistor goes off and only a pullup keeps it high; you can pull it low from outside. JW |
| Topic | Author | Date |
| About I/O 89C52 | 01/01/70 00:00 | |
| what about reading this thread | 01/01/70 00:00 | |
| hmm ? | 01/01/70 00:00 | |
| So, read it. | 01/01/70 00:00 | |
| but | 01/01/70 00:00 | |
| yes | 01/01/70 00:00 | |
| reread the "bible" | 01/01/70 00:00 | |
| so | 01/01/70 00:00 | |
| bfore reading a 1 read the bible | 01/01/70 00:00 | |
| Ports | 01/01/70 00:00 | |
pullup + loading capacitance | 01/01/70 00:00 | |
| No | 01/01/70 00:00 | |
| so that's true ? | 01/01/70 00:00 | |
| no else if | 01/01/70 00:00 |