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Help needed programming PBASIC2/P — Parallax Forums

Help needed programming PBASIC2/P

I am having trouble programming a PBASIC2/P.

First, the documents I have found show the pinouts for this chip, a 16F57-I/P, 28-pin std DIP, to be the same as the SX28DP/AC which is a 28-pin skinny DIP.

Second, I have been able to program the skinny DIP, 50 MHz, but not the standard-size DIP, 20 MHz. Clock signal comes from a CTS MXO45HS oscillator module of the correct frequency.

Third, clicking the IDENTIFY button in editor reports: BASIC Stamp 2 V1.0; Loopback=yes; Echp=yes
F9 yields: Download Error BASIC Stamp 2sx not found...

Does anyone have an idea what may be going on?




  • Are you using the interpreter chip for the BASIC Stamp2sx or 2p?
    If it is for a 2p, your first two lines of code should look like this:
    ' {$STAMP BS2p}
    ' {$PBASIC 2.5}
    If it is for a 2sx, your first two lines of code should look like this:
    ' {$STAMP BS2sx}
    ' {$PBASIC 2.5}
  • Apparently, the editor believes it's a BS2, so I let it change the statement to {$STAMP BS2}

    Now F9 yields:

    Hardware communication failure! Check programming cable and power supply."

    If I replace the chip with one of the skinny DIPs and replace the 20 MHz osc with a 50 MHz unit, the editor correctly identifies the skinny chip as a BS2SX V1.3 and programs it as it should. Programming cable/interface and power supply are the same.

    What am I missing???
  • AwesomeCronkAwesomeCronk Posts: 1,055
    edited 2019-12-31 18:10
    Could you post a close-up image of the two DIPs in the circuits?
  • Are these actual Parallax BS chips or just Microchip. Microchips do not have the Basic Stamp interpreter installed. They have to be pre programmed at Parallax.
  • The skinny DIPs are Parallax SX28AC/DP-G. I am able to program them.
    They were sold to me by Parallax as PBASIC2SX/P

    The 3 std DIPs are Microchip 16F57-I/P. I am unable to program any of them.
    Two were sold to me by Parallax as PBASIC2_P and
    one was sold to me by Jameco asPBASIC2/P.

    So, I don't really know what the 3 16Fs are...

    I'll try to post photos
  • Photos as requested:
    3264 x 2448 - 3M
    3264 x 2448 - 3M
  • Mike GreenMike Green Posts: 23,047
    edited 2020-01-02 16:45
    The 16F57 DIPs with the Microchip logos stamped on them are not Parallax Stamp microcontrollers. You won't be able to program them using the Stamp editor. Parallax does use the Microchip 16F57 to make BS2 Stamps by factory programming them with the Stamp interpreter. If, for some reason, the 16F57s have been erased, you can send them back to Parallax to be re-programmed.

    Note: The 16F57 is a perfectly fine microcontroller made by Microchip. It can be programmed in C and in Basic (not the same as Parallax's Basic). These require some sort of programming adapter. Do a web search for "microchip basic programming" for all sorts of information from Microchip, MELabs, and others.
  • Thanks for the insight, Mike. It does look as though the 16Fs do not contain the Stamp interpreter. I will contact Parallax and look into having the program installed.
    Best regards,
    Larry Salter
  • My PBASIC program will load via the serial interface on pins 8,9 & 28, same as on the skinny DIP, is that correct?
    Built a new programming board with sockets for the BS2sx 28-pin skinny DIP and the BS2 28-pin std DIP so I can program either with the same hardware by simply swapping out the PBASIC chip and the crystal oscillator module. Still getting the same results:

    1) skinny DIP ID's as BS2SX v1.3 and loads/runs my PBASIC program correctly. Oscillator freq. is 50 MHz. This is with the program directive ' {$Stamp BS2SX}

    2) std 0.6" DIP which is a PBASIC2/P (PIC 16F57-I/P)) ID's as BS2 v1.0 but will not load/run my PBASIC program. "ERROR- Hardware Communication Failure. Check Power and Cable" Oscillator freq. is 20 MHz (+299 Hz). This is with the program directive ' {$Stamp BS2}

  • Good morning Mike Green,

    After talking with Chantal at Parallax, they sent me replacement chips. The replacements are also marked Microchip PIC16F57-I/P and exhibit the same issue: I still cannot program them with a programming setup that I know works on the sx OEM ICs. I am at a loss to know how to obtain the OEM chips- either the SX28AC/DP (preferred) or alternatively, PBASIC2/P (0.6" DIP)
    I appreciate any help you can offer.

  • They are probably just a standard Microchip PIC16F57-I/P and not programmed with the BS Interpreter. Parallax has indicated they will not be programming any more Interpreter chips, which hurts me as I have over 100 chips to be programmed with a few different Interpreters.
    What Parallax part number did they send you?
  • They were ordered as PBASIC2/P OEM chips. Some came from Jameco and some direct from Parallax, but all were sold as PBASIC2/P chips with the interpreter pre-programmed.

    The invoice lists them as:
    Item: PBASIC2/P Desc: PIC16F57 w/BS2 v1.0

    How can I determine if the interpreter is resident?
  • You may need to go back to to verify what you were shipped. Jameco seems to be a standard BS2 interpreter. neither on is an SX if that is what you were looking for.
  • I, too, thought the Jameco part was a standard BS2 interpreter when I ordered them.
    I wasn't looking specifically for SX chips, it's just that I have a few of the skinny DIP SXs and am not having any problems whatsoever with them. If I could get more of those, I would. I only bought the PBASIC2/P std DIP chips because the SX28AC/DP were out of stock.

    I have an (E)EPROM programmer and read one of the 16F57 chips. There was data of some sort from $000 to $03F and $0000 from $040 through $7FF. Does this suggest anything?
  • I guess the question is, what do you ultimately what to end up with?
  • Well, I would like to end up with PBASIC2/P standard 28-pin, 0.6" DIPs that I can program with my current serial programming arrangement which I know works with the SX28AC/DP chips.

  • Unfortunately, the code that is needed to program a DIP-28, or any variation, to turn a PIC into an Interpreter, is Intellectual Property, (code), owned by Parallax.
    I spoke with David Carrier at Parallax Tech Support about this issue and he suggested changing the EEPROM from a 24LC128I/P to a 24LC16B/P, something I had not done up to this point. Swapped it out and VIOLA all is now good!

    MANY thanks to everyone who responded!!!

  • I am glad it was solved!
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