Re: [fpc-pascal] Re: (OT) Re: How to use UART of ARM platforms (e.g. Raspberry Pi ) through free Pascal?
On 07/04/2013 05:24 PM, Mark Morgan Lloyd wrote: In any event, my experience is that USB-serial converters are very poor Same here ! Standard USB stuff is not really suitable for embedded use. Due to electrical disturbances the data on the USB line can be corrupted and the link between host and device can be lost. In that case the _device_ needs to initialize a reconnection. The host can't do that because the protocol does not offer this option. But OTOH in many cases the device can't detect that the link is lost at the host. You can help this by doing your own software in the device and implement a life check protocol. But Standard devices don't feature this. -Michael ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Re: (OT) Re: How to use UART of ARM platforms (e.g. Raspberry Pi ) through free Pascal?
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. 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. -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Re: (OT) Re: How to use UART of ARM platforms (e.g. Raspberry Pi ) through free Pascal?
Al 04/07/13 17:24, En/na Mark Morgan Lloyd ha escrit: 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. Not if the converter manages the rx/tx switching all by itself 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. The ones I used worked with the standard driver: send something, it automatically enables the transmitter, after the last bit has been transmitted it goes in high impedance mode ready for listening/receiving. Bye -- Luca ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Re: (OT) Re: How to use UART of ARM platforms (e.g. Raspberry Pi ) through free Pascal?
Hi, Can this thread please be moved to the fpc-other list? Thanks, Jonas FPC mailing lists admin ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
