| ??? 03/05/08 16:42 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#151921 - once is enough Responding to: ???'s previous message |
1) I'm using port 0 as a keypad input, but instead of running it directly from the keypad to the controller I'm interfacing through some 74LS148s (keypad is 12 pin, not 8 pin matrix). Am I correct in the assumption that I don't need any pullup resistors, as I would if I connected a 8 pin matrix directly to port 0 (as I did on my last project), when the input actually comes from the 148s?
the 148 has (do check) totem-pole outputs so no pullup will be required. 2) If I'm only using port 0 for input, always, do I need to set P0 to 0xFF every time I want to read from the port (or is once enough)? once is enough Erik |
| Topic | Author | Date |
| Two quick questions about Port 0 | 01/01/70 00:00 | |
| once is enough | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
zero is enough | 01/01/70 00:00 |