Post by thread:[PICLIST] pic 256 keypad combination

Hi all, want to have 256 input keys for the 8 ports on pic16f84. A real headache when have to connect all 8 ports to ground and then switch back. anybody tried something like PLA ? Any help is greatly appreciated. Yansong -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

> want to have 256 input keys for the 8 ports on pic16f84. Can you use a remote control chip like the ones that Philips or Sony make ? Some of these can detect several hundred keys. They are 1-wire serial. The ones I've used are organised in banks of 64 (for one keypress) and select lines for another key to select which bank of 64. Most of them allow only one key at a time to be pressed in the block of 64, and one other key to select the 64-key block, kind of like Shift/Ctrl /Alt on a PC > A real headache when have to connect all 8 ports to ground > and then switch back. Don't understand -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spam_OUTlistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

Thanks for the suggestion. Going serial is a good idea at the cost of one additional component though. The 8 connection goes like this: They were supposed to all connect to gound at the moment when one keypress is excised. then they immediately come back to 1. This will be interpreted as a value of 255. One way to physically do this is have all 8 wires goes very close together and one touch-down connects all to a gournd wire(if ever possible) By the way mind telling me what key word to search for the philips/sony chip? Yansong {Original Message removed}

> By the way mind telling me what key word to search for the philips/sony > chip? > > Yansong SAA3000 series. They should be still around. Or you could pop the back off any TV/VCR/stereo IR remote and have a look. I'd expect they'd be made by quite a number of companies Try looking around http://www.chipdir.com for remote control ICs -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body