| ??? 09/04/09 21:19 Read: times |
#168733 - Of course you should be an input Responding to: ???'s previous message |
Write a '1' to the pin to make it an input.
Depending on your PIR module it may be safer to "help" with an external pull-up. The important thing is to make sure the INT0 pin gets predictable voltages. e.g. if you are using a transistor as an inverter you must calculate the currents and voltages correctly. Your transistor must be off when the PIR o/p is below 2.5V and switched hard on when PIR o/p is above 2.5V. The transistor will need an external collector resistor. The 8051's internal pull-up is probably too weak. David. |
| Topic | Author | Date |
| Is pull-up needed for INT0 / INT1 | 01/01/70 00:00 | |
| Is the PIR output open collector? | 01/01/70 00:00 | |
| PIR is inverted using a BC547 | 01/01/70 00:00 | |
| Use a base-emitter resistor | 01/01/70 00:00 | |
| /INT0 : write 1 to config as i/p pin ? | 01/01/70 00:00 | |
| Of course you should be an input | 01/01/70 00:00 | |
Don't think that way! | 01/01/70 00:00 |