| ??? 01/20/05 14:49 Read: times Msg Score: -2 -1 Gimmee Code -1 Didn't Search First |
#85411 - how to scan a matrix keypad |
hi
i have connected the 5X4 matrix keypad to 82c55 i/o chip , rows at pb0 to pb4 and columns at pc4 to pc7. also i have generated interrupt pulse for ex0 of 89c52 when key pressed. i want controller to scan the keys at every 500msec and the debounce time is 20msec.also when keypressed the led connected at p1.7 should glow to confirm the key detection. can anybody give the code in assembly for scanning the key and jumping on that key's code. hemant |
| Topic | Author | Date |
| how to scan a matrix keypad | 01/01/70 00:00 | |
| no code give | 01/01/70 00:00 | |
| says he is.. | 01/01/70 00:00 | |
| Didn't search first | 01/01/70 00:00 | |
| 82C55 | 01/01/70 00:00 | |
| Reasons for using 8255 | 01/01/70 00:00 | |
| Maybe. | 01/01/70 00:00 | |
| Where do they get them? | 01/01/70 00:00 | |
| Well... | 01/01/70 00:00 | |
| Easily available | 01/01/70 00:00 | |
| Gopal: Are you sure. | 01/01/70 00:00 | |
| price ratio | 01/01/70 00:00 | |
| Parts in Mexico | 01/01/70 00:00 | |
| Maybe but | 01/01/70 00:00 | |
| 8255 | 01/01/70 00:00 | |
| Re: 8255. | 01/01/70 00:00 | |
| Not outdated | 01/01/70 00:00 | |
| Market | 01/01/70 00:00 | |
| Opportunities? | 01/01/70 00:00 | |
| Kerching | 01/01/70 00:00 | |
| Kerching | 01/01/70 00:00 | |
| Who'll buy that ? | 01/01/70 00:00 | |
| How about... | 01/01/70 00:00 | |
| Diplomacy | 01/01/70 00:00 | |
| What's in a name? | 01/01/70 00:00 | |
| Checkmate | 01/01/70 00:00 | |
| Hobbyist Magazines | 01/01/70 00:00 | |
| video killed the radio star | 01/01/70 00:00 | |
| IT and Call Centre NOT Electronics. | 01/01/70 00:00 | |
| Reasons for this trend | 01/01/70 00:00 | |
| You are right Gopal. | 01/01/70 00:00 | |
| Pay Craig for advertising | 01/01/70 00:00 | |
| David, We are not alone | 01/01/70 00:00 | |
| OK | 01/01/70 00:00 | |
| I am also a culprit | 01/01/70 00:00 | |
| No 20 years | 01/01/70 00:00 | |
| OT: no citizenship | 01/01/70 00:00 | |
| Intersil manufactures it | 01/01/70 00:00 | |
| Bogus 8255. | 01/01/70 00:00 | |
| outdated, what? | 01/01/70 00:00 | |
| A more neutral point of view! | 01/01/70 00:00 | |
that is not the reason | 01/01/70 00:00 |