| ??? 08/26/04 13:16 Read: times |
#76444 - You need a 1-Wire per reader Responding to: ???'s previous message |
Shahzad said:
A 1-Wire means there is only one wire connecting all readers. if a ibutton generates a reset pulse that will go on the one wire. how the micro will determin whihc reader generate the reset Quite simply, it can't! :-( It's the same as my problem of associating multiple temperature sensors with their locations: http://www.8052.com/forum/read.phtml?id=67682 You will need to either: 1. run a separate 1-Wire link to each reader, and provide multiple 1-Wire ports on your central controller, or 2. have a small micro with a 1-wire port at each reader. You could then link all your readers back to the central controler on a (separate) 1-Wire bus, or use something else - such as RS485, or whatever. If you go for option 2, you would probably also get the local processor to activate the door lock mechanism; it could also drive flashing lights, and other bells & whistles... See http://www.8052.com/forum/read.phtml?id=76109 |
