On 04/07/2013 16:24, Mark Morgan Lloyd wrote: > Lukasz Sokol wrote: >> On 04/07/2013 12:03, Michael Schnell wrote: >>> On 07/04/2013 12:52 PM, Lukasz Sokol wrote: >>>> For RS485 adaptation, use a MAX232 like chip (to convert +-12 >>>> to ttl) and then a RS485 transceiver chip; >>> If you want to create hardware anyway, better use a PIC24 (pr >>> PIC32) chip with USB plus a RS485 tranceiver chip. So you get rid >>> of the " ATEN usb-to-serial cable (UC-232A)" and you have both >>> sides of USB under your control so that you can do the USB >>> procedure you want. >>> >> +1 if OP wants to create his own hw and sw for that purpose >> >>> Another way is using a pre-programmed PIC chip available by >>> Microchip with USB to-Serial software plus a RS485 tranceiver >>> chip. >>> >> +1 if OP wants to use standard hw... > > Discussion elsewhere suggests that the RPi has an internal 16550 > port, and controlling the 485 signals using e.g. CTS might be > viable.
Yeah I seem to remember http://www.hobbytronics.co.uk/raspberry-pi-gpio-pinout I guess for 485 direction setting, one of GPIO will need to be used; Sigh. Why do people keep reinventing ethernet starting from half duplex without galv. separation ? :) > > In any event, my experience is that USB->serial converters are very > poor for anything that involves accurate timing, and I suspect that > controlling a 485 transceiver in conjunction with one would be > problematic. I think I asked FTDI about this a couple of years ago, > and was told that their hardware had facilities that would help but > exploiting them would take a non-standard driver. > Well that's a question of OP's project goals agenda... -L; _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
