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BS2 SIN/SOUT Pins, MAX232 and not enough caffeine... — Parallax Forums

BS2 SIN/SOUT Pins, MAX232 and not enough caffeine...

JordanCClarkJordanCClark Posts: 198
edited 2012-04-19 07:03 in BASIC Stamp
I've read enough on this to make my head spin... so what I'm trying to take away from all this is:

Do I need to add a MAX232 to the program port of a BS2, or is that more for if I was going to use an I/O pin for serial comms?

I've already got a board made up with a MAX232 attached to the serial pins, but I'm a-thinkin' that my thinkin' was stinkin' and these boards are now mostly useless-- not a big deal, because my next board rev is adding circuits for other things anyway, but the comms issue came and bit me. Feel free to laugh at my expense-- after all, if I can't laugh at myself, then there's plenty of other people to take up the slack! :lol:

Thanks in advance!

Regards,

Comments

  • Martin_HMartin_H Posts: 4,051
    edited 2012-04-19 05:13
    The $50 Basic Stamp module used with the Board of Education and Boe-bot uses RS232 voltage and inverted logic. All it needs are two capacitors, one between DTR and the ATN pin and another between that and ground. The documentation has a schematic for doing this.

    The OEM version is discrete chips and is meant to be used in vendor products. It uses TTL voltage and logic, so a MAX232 is used to hook it up to a serial port.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2012-04-19 05:45
    Measure twice, cut once.
    - Norm Abrams

    BS2_expl.JPG
    BS2_expl.JPG
    517 x 249 - 17K
  • JordanCClarkJordanCClark Posts: 198
    edited 2012-04-19 07:03
    Thanks for the info, guys, I had all the info (schematics and such), but just had trouble visualizing the final bit.

    I had jumpered the board around the max232 socket, but still had no joy. It's part of what prompted my original post.

    But then I found two things wrong with my board.

    1. I had the two caps in, but nothing going to the ATN pin-- efectively two caps in serial between DTR and ground.
    2. The footprint in my PCB software apparently made distinction between a male or female conector, so the pinout was incorrect.

    That'll teach me to try and design a board after a 30 hour work stint. Too many irons in the fire, and the barn's burning... now where's that smiley for an eye roll?

    EDIT: Forgot to add my final results: after soldering in a jumper to the ATN and making a "mega-crossover" cable (1-5, 2-4, etc.) I got a response from the BS2. I can finish out the testing and get a revised board made after that.

    Thanks again!

    Regards,


    Just to let y'all know, I found two other things wrong. The
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