| ??? 09/25/07 15:59 Read: times |
#144990 - make a full terminal from U3 Responding to: ???'s previous message |
It seems to me that you have a "helper" '2051 - U3 - for the keyboard scan. You might consider to make a full "terminal" out of it - use the few spare lines and a serial-in-parallel-out shift register (perhaps also with a latch - see 74HC595) to expand the number of your ports.
As it connects via UART to the "main" '51, you will then be able to get to a modular conception, where you can replace the keyboard/LCD combo by a RS232-level-convertor and a cable to PC, so that you can control the programmer relatively comfortably from PC - where a PC is available. In this way you will get rid of the conflict on P0. Of course there are many ways, but I'd see as a priority to resolve the conflict on P0. JW |
| Topic | Author | Date |
| AT89c2051 power up sequence | 01/01/70 00:00 | |
| any schematics? | 01/01/70 00:00 | |
| No schematics right now | 01/01/70 00:00 | |
| at least... | 01/01/70 00:00 | |
| Single step | 01/01/70 00:00 | |
| And what was it, then? | 01/01/70 00:00 | |
| RE: And what was it, then? | 01/01/70 00:00 | |
| what LCD? | 01/01/70 00:00 | |
| RE: what LCD | 01/01/70 00:00 | |
| OK so why was the LCD blank? | 01/01/70 00:00 | |
| RE: OK so why was the LCD blank? | 01/01/70 00:00 | |
| data conflict/posting pictures | 01/01/70 00:00 | |
| RE:data conflict/posting pictures | 01/01/70 00:00 | |
| Schematics | 01/01/70 00:00 | |
| Complete schematic | 01/01/70 00:00 | |
| please use smaller pictures and png/gif | 01/01/70 00:00 | |
| Done | 01/01/70 00:00 | |
| Using 2051 | 01/01/70 00:00 | |
| make a full terminal from U3 | 01/01/70 00:00 | |
| Add some diodes | 01/01/70 00:00 | |
| RE:Add some diodes | 01/01/70 00:00 | |
| Multiplexing | 01/01/70 00:00 | |
| Pull ups | 01/01/70 00:00 | |
| Not required. | 01/01/70 00:00 | |
try this code | 01/01/70 00:00 |