On Mon, 5 May 1997 15:37:27, Antonio Almeida wrote: > Does anyone has some ideas on how to do a poor man's version of > Plug-and-Play ? I need it to implement a network (maybe using RS485), and > i want to insert nodes automatically, without the need for the person who > plug's the node to know what's happening. Any ideas, comments ?... Dallas Semiconductor, http://www.dalsemi.com, has a slow 1 wire protocol that allows a master device to probe the bus and find all the devices. Each chip that supports the protocol has a unique serial number. You can impliment the protocol with a PIC and RS-485, as long as the RS-485 has a pull-up resistor, so the idle bus always goes to the same logic level. You need to make sure each device has a unique serial number, or the scheme fails. You'll also need some information describing the board configuration. An easy way to do it, is to include a Dallas Semiconductor part with eeprom on your board. Use the part's serial number for the board's serial number and the EEPROM to hold the board configuration information. I think the DS2430A would work, if 32 bytes of eeprom is enough to store your config info. You can do the same thing with just a PIC, if it has EEPROM, or even OTP, as long as your manufacturing folks can store unique information in each PIC. -- paulh@hamjudo.com http://www.hamjudo.com The April 97 WebSight magazine describes me as "(presumably) normal".