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Additional serial I/O — Parallax Forums

Additional serial I/O

coder1024coder1024 Posts: 9
edited 2006-06-28 11:38 in BASIC Stamp
What components would you reccommend for adding additional serial (RS-232) I/O to my BASIC Stamp HomeWork Board (the one that comes with the Activity Kit)?

I'd like to read a data stream from an RS/232 device and write to another one.· I don't want to use the debugging port as I'd like to be able to use DEBUG during execution to monitor whats happening.

Is there an easy way to add additional RS-232 serial lines to my HomeWork Board?

Thanks!

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-06-11 21:04
    Parallax RS232 AppMod, as easy as it gets -- http://www.parallax.com/detail.asp?product_id=29120
  • coder1024coder1024 Posts: 9
    edited 2006-06-12 00:25
    Looks like a nice component. I noticed the below, however, and wonder if I can get it to work with my BASIC Stamp HomeWork Board?

    "The RS-232 AppMod is compatible with Parallax development boards that feature the 2x10 AppMod connector"

    My board doesn't have the AppMod connector.· Think I can just hook it up to the I/O pins via the breadboard?
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-06-12 00:50
    You could probably finnagle something that way, devise your own header adapter, flying leads, that sort of thing.
  • coder1024coder1024 Posts: 9
    edited 2006-06-12 00:53
    Is the AppMod connector just a way to connect up to the I/O pins? Or does that connector hook up elsewhere to the chip?
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-06-12 00:58
    I was just looking at that.· In the "larger view" picture I see the SIP-row with RX, TX, CTS, RTS -- those are the TTL sigs you'd run to your STAMP pins.· I was looking around for a schematic for it to find out how/where it brings in +5V and GND.

    Post Edit --
    Looks like pins 1 & 2 of its "X1" are for ground (VSS) and pin 19 is for +5V (VDD).
    You'll need to be "handy".

    Post Edited (PJ Allen) : 6/12/2006 1:06:34 AM GMT
  • allanlane5allanlane5 Posts: 3,815
    edited 2006-06-12 14:07
    Note that the BS2 has no 'serial buffer'. This means that unless the BS2 is 'waiting' in a SERIN statement for serial data, it's going to get dropped on the floor. So if the BS2 is 'sending' data in a SEROUT, it can't at the same time be recieving data in a SERIN.

    This limits the BS2's use as a serial buffer device, checking more than one serial port at a time.

    Oh, and there do exist small co-processors that will act as serial buffers for RS-232 information, which will hold the data until the BS2 can get around to dealing with it.·
  • coder1024coder1024 Posts: 9
    edited 2006-06-28 11:38
    maybe the thing to do would be to have a set of buffers, one for each serial interface and in the main loop have the code do a round robin servicing of each interface, 1 byte at a time. Although, I'm not sure I can do non-blocking reads...
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