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High Speed Serial — Parallax Forums

High Speed Serial

jpuckettjpuckett Posts: 3
edited 2009-05-22 03:25 in BASIC Stamp
I need to send an initiallization string of 30 or 40 bytes then listen for a message of less than 50 bytes.· I need to do this once per second or so but here is the catch, it needs to be at a bit rate of 115K.· Does anyone have any ideas?· Perhaps a UART?· Any recomendations?· The basis Stamp needs to drive a display with the information it receives from the data.· But I can do that.· I do not believe the Basic Stamp can operate that fast.· Again this only happens once every second or perhaps half second.·

Jeff

Comments

  • vaclav_salvaclav_sal Posts: 451
    edited 2009-05-19 03:04
    Friend,
    check this "BS2 execution times" out.
    It may give you an idea how fast (or slow) you can accomplish "high" speed data transfer using just input and output "low level" BASIC.
    By that I mean - no SERIN or SHIFTOUT "complex" commands.

    http://www.emesystems.com/BS2speed.htm

    Cheers Vaclav
    ·
  • jpuckettjpuckett Posts: 3
    edited 2009-05-21 19:44
    Has anyone ever interfaced a uart such as the TI 16C750 to a basic stamp?

    Jeff
  • Mike GreenMike Green Posts: 23,101
    edited 2009-05-21 20:00
    The Stamps cannot operate that fast, particularly for receiving. You might be able to use an SX to do what you want, but I don't think you'll get the amount of buffering you'd need. It would be trivial to have a Propeller do this. It can do full duples serial I/O at 230K. The serial driver that's included with the Propeller Tool has only a 16 character buffer, but there are alternative versions in the Propeller Object Exchange that have up to 256 character buffers.

    The 16C750 and its relatives would not be easy to interface to a Stamp. They're designed for direct connection to a memory-mapped CPU and require an external Baud clock generator. You could do it, but it would take a lot of additional logic.

    The Maxim MAX3100 is a better interface fit to something like a Stamp, but it only has an 8 byte buffer and a Stamp may not be able to keep up at 115KBaud.
  • jpuckettjpuckett Posts: 3
    edited 2009-05-22 01:08
    I did not know the propeller was a different product. The Basic Stamp was recommended I have never used one before. I bought the kit. I will order a propeller kit, that is not a problem. My application is simple but because of the high baud rates it has become too complex. I am currently using a PC but I can not leave a PC where we need this to operate.

    My code skills are not that good, I am basically a hardware guy, is the programming for the propeller much different than the Basic Stamp?

    I will order a developement kit today.

    Thanks,
    Jeff
  • kwinnkwinn Posts: 8,697
    edited 2009-05-22 01:44
    The programming is different, but there are objects available for a lot of functions and the folks in this forum are very helpful if you have questions.
  • Mike GreenMike Green Posts: 23,101
    edited 2009-05-22 03:25
    The Propeller has the ability to drive a VGA display and/or a TV display directly (with a couple of resistors and the proper connector). It's also fast enough and has enough memory to be able to do floating point at a reasonable speed. The Propeller Demo Board has the video interface hardware built-in and the Propeller Protoboard has VGA output as an option (with the Accessory Kit).
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