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fastest way to communicate with a pc. — Parallax Forums

fastest way to communicate with a pc.

DXCDXC Posts: 33
edited 2010-08-16 10:53 in Propeller 1
Hello all,

I am working on work on a big test machine.
As test will hebben on products they will have to go fast,time is money.

Setup is:
- PC sending commands.
- relay switch box controlled with a prop.

Which connection would be the best, just the USB-FT232, ethernet....?

gr,

Comments

  • KyeKye Posts: 2,200
    edited 2010-08-13 12:43
    The USB FTDI connection can hit up to 2Mbs.

    If your just controlling relay's then I wouldn't even worry about speed.
  • LeonLeon Posts: 7,620
    edited 2010-08-13 13:05
    High-speed USB with a Vinculum chip is 480 Mb/s, but the Propeller won't be able to keep up.
  • DXCDXC Posts: 33
    edited 2010-08-14 00:12
    Thnx for the reply.
    Speed is indeed not the main factor but ethernet looks nice to have, Im going to put a ENC28J60 in the schematics, and use the prop + ft232 for the time being.

    Kye,
    How can you have speeds of 2mb/s with a ft232 and pc?
    The pc max setting on com ports are 110kB/s or how do I set my com ports?
    Or do I have to use another ft232 chip like?

    gr,
  • jmgjmg Posts: 15,185
    edited 2010-08-15 12:39
    DXC wrote: »
    Thnx for the reply.
    Speed is indeed not the main factor but ethernet looks nice to have, Im going to put a ENC28J60 in the schematics, and use the prop + ft232 for the time being.

    Why not target the FT2232H ?

    Only slightly more expensive than the cheapest one, and you get a 480M core,
    so can get > 10MBytes/s

    These have FIFO, SPI, JTAG modes, so you can choose speeds.
  • ke4pjwke4pjw Posts: 1,173
    edited 2010-08-16 09:03
    DXC wrote: »
    Hello all,

    I am working on work on a big test machine.
    As test will hebben on products they will have to go fast,time is money.

    Setup is:
    - PC sending commands.
    - relay switch box controlled with a prop.

    Which connection would be the best, just the USB-FT232, ethernet....?

    gr,

    The fastest I have been able to achieve is with the FTDI FT245. Mouser sells the breakout board.
    3Mbits/second with the virtual com port. I imagine you can go faster using using the D2XX drivers. They go to 10Mbits/second.

    See my sig for the FullDuplexParallel object for use with the FT245.

    PS- You will need 12 data lines open on the prop.
  • FredBlaisFredBlais Posts: 380
    edited 2010-08-16 09:58
    ke4pjw wrote: »
    The fastest I have been able to achieve is with the FTDI FT245. Mouser sells the breakout board.
    3Mbits/second with the virtual com port. I imagine you can go faster using using the D2XX drivers. They go to 10Mbits/second.

    See my sig for the FullDuplexParallel object for use with the FT245.

    PS- You will need 12 data lines open on the prop.

    Does it still use a virtual com port? I think the problem might be on the computer side, it always try to buffer data before we can access it.

    BTW, it's fascinating how my thread name (that I started this month) and this one are similar
  • ke4pjwke4pjw Posts: 1,173
    edited 2010-08-16 10:53
    FredBlais wrote: »
    Does it still use a virtual com port? I think the problem might be on the computer side, it always try to buffer data before we can access it.

    Yes, you can use the VCP driver. The 3Mbit and 10Mbit limits are limitations of the FTDI chip and the driver used (VCP and D2XX respectively). I have not seen any serial methods that can achieve speeds > 512Kbits, with 100% reliability. I have been able to pump 3Mbps through to the prop with the VCP driver and this parallel method. I have not performance tested the D2XX driver, so I don't know what the upper bounds is for my object. As best I can tell, this method is as fast as it gets with the prop.
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