Hi, thanks for your suggestion. It is very useful for mine. I would like to wish to you and to your familiy BUONA NATALE E BUON ANNO Ciao Leonardo -----Messaggio originale----- Da: M.v.d.Bilt A: PICLIST@MITVMA.MIT.EDU Data: sabato 19 dicembre 1998 17.04 Oggetto: Re: Multiple 16F84 in multidrop serial >appel's desktop bus works lik this there is an appnote on microchip's >website an519 i improved the code for differend application apple >allowed 16 device's to be connected to the Adb bus works with polling >by the host > >greetings an happy christmas to all >Marcel >M.v.d.Bilt@fibre.A2000.nl > >Donald L Burdette schreef: > >> There's a simple way to "or" the slave TX lines with just one resistor. >> Just tie several open collector outputs together and use a single pullup >> resistor. >> >> Almost all Microchip I/O pins can be configured as open collector. Set >> the data register to 0, and write the data to the direction register. >> When the data is "1" the pin is tri-state, when the data is "0" the >> output pulls low. I've used this method to tie several Dallas 1-wire(tm) >> parts to a single I/O pin. That's why they call it 1-Wire! >> >> Such a configuration is not high speed compared to RS-485, but it could >> go at 19.2 kBaud over 20 meters without even really trying hard. I've >> worked it at equiv to 9.8 kBaud at 300 meters. With 2 or 3 line >> protocols you could go significantly faster. Is 19.2 kBaud fast enough? >