| ??? 09/11/04 02:26 Read: times |
#77237 - Port0 cannot emit high level Responding to: ???'s previous message |
i want to use port 0.0 0.4 for scanning the columns and port 2.0 to 2.4 for scanning the rows
Hallo Huzefa, I don't know your circuit, but keep in mind, that Port0 has open drain outputs, which cannot emit logical high levels!! When writing 1s into according SFR register, open drain outputs are floating, means they look very high ohmically, as if nothing is connected to it. If you expect Port0 outputs to emit high level in your scanning routine, then your application will fail. Kai PS: Please don't hesitate to come back and discuss with us. If you see us being a bit upset, then it is because you dissapeared in your last thread... |
| Topic | Author | Date |
| matrix keyboard interfacing to 8051 | 01/01/70 00:00 | |
| RE: matrix keyboard interfacing to 8051 | 01/01/70 00:00 | |
| Schematic, code, and test the circuit | 01/01/70 00:00 | |
| RE: Schematic, code, and test the circuit | 01/01/70 00:00 | |
| RE: Schematic, code, and test the circuit | 01/01/70 00:00 | |
| RE: Schematic, code, and test the circuit | 01/01/70 00:00 | |
| Port0 cannot emit high level | 01/01/70 00:00 | |
| RE: Port0 cannot emit high level | 01/01/70 00:00 | |
RE: Port0 cannot emit high level | 01/01/70 00:00 | |
| Debugging time | 01/01/70 00:00 | |
| RE: matrix keyboard interfacing to 8051 | 01/01/70 00:00 | |
| RE: LEDs and UART debug | 01/01/70 00:00 | |
| ALE vs LED | 01/01/70 00:00 | |
| RE: ALE vs LED | 01/01/70 00:00 | |
| Flow chart | 01/01/70 00:00 |