Al 04/07/13 11:16, En/na Dennis Poon ha escrit: >> With RS-485 hardware you can - and supposedly need to - do >> "half-duplex with output enable", if your hardware provides this. >> > After days of google search, I am afraid the bcm2835, the Soc of > Raspberry Pi (the hardware I have to use) does not provide this hardware > support :-( > It states that it does not even support interrupt. Polling is the only > way for events :-(
If that's true, you could use an usb to rs485 adapter, most of those do the tx/rx switching automatically, so you just see a "normal" serial port (of course you'll have to manage the high level protocol yourself). I've mostly used them in 422 mode (4 wires/full duplex) but I used one of them once in rs485 mode (2 wires/half duplex). IIRC the brand was VSCom. Bye -- Luca _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
