| ??? 04/08/06 16:55 Read: times |
#113916 - What might offer a shorter path Responding to: ???'s previous message |
to a solution is a pin-compatible 805x MCU.
If you look at my local homepage, you'll find a picture of the inside of the keypad, showing the SIGNETICS 24-pin MCU that it uses as an encoder and ADB interface. Now, if that were replaced with another pin-compatible MCU (I'd like to use the on-board resonator and reset circuit, and probably the key matrix connections as well) then I could encode the keypad as I like and use some 2-wire protocol already standardized on 805x, with which to put out the HEX data I need. What's also possible, is that I could simply use the 2 wires to put out clock and data and feed a shift register at the receiving end with the data. My present keypad interfaces use the 74C923, which is a 20-key encoder, as the keypad matrix interface, via a 9-wire cable. RE |
| Topic | Author | Date |
| Has anybody used the ADB | 01/01/70 00:00 | |
| btw ... about that search ... | 01/01/70 00:00 | |
| What you need is.... | 01/01/70 00:00 | |
| What might offer a shorter path | 01/01/70 00:00 | |
| seems like a lot of trouble ... | 01/01/70 00:00 | |
| There's plenty of info on the web | 01/01/70 00:00 | |
| There's a gotcha | 01/01/70 00:00 | |
I took another look, | 01/01/70 00:00 |