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Prop Backpack being revisited — Parallax Forums

Prop Backpack being revisited

Hello!
Here we are about six years since I looked into how the Prop Backpack that @"Phil Pilgrim (PhiPi)" created for Parallax created video and gave us the chance to see our BASIC Stamp programs display their activities on the video screen. I took a chance last night, and this morning to investigate why my original program series did not properly understand how logic applied to signals worked out. It turns out I chose the wrong chip. Instead of the SN7437, I switched to the SN7423. And found there was a noticeable indication. In this case there was a blinking Red LED present.

(Code attached!)

And that above did perform as expected. Eventually I tossed in a previously programmed in PAL chip. And of course it works. While the selected variable output lines did not change, at least there's a visible change on the logic connected.

Mascot baffled. Also asleep.

Comments

  • Here:

    ' =========================================================================
    '
    '   File...... screentest8.bs2
    '   Purpose... screener
    '   Author.... GCL -- Jedi Knight Computers
    '   E-mail.... gregg@levine.name
    '   Started... 10 Mar 2014
    '   Updated... 11 Mar 2014
    '
    '   {$STAMP BS2}
    '   {$PBASIC 2.5}
    '
    ' =========================================================================
    
    ' -----[ Program Description ]---------------------------------------------
    
    ' This program outputs video to an NTSC color monitor via a Propeller
    ' Backpack module and demonstrates the various features of the video driver.
    
    
    ' -----[ I/O Definitions ]-------------------------------------------------
    
    io     PIN 15           ' Serial I/O pin for Propeller Backpack.
    U1A    PIN 0
    U1B    PIN 1
    U1C    PIN 2
    ' -----[ Constants ]-------------------------------------------------------
    
    ' Baudrate definitions. Serial I/O must be open-drain. The Propeller Backpack
    ' includes a pullup internally.
    
    #SELECT $STAMP
      #CASE BS2, BS2E, BS2PE
        baud    CON  84 + 32768
      #CASE BS2SX, BS2P
        baud    CON  240 + 32768
      #CASE BS2PX
        baud    CON  396 + 32768
    #ENDSELECT
    
    ' The following is a table of "command" constants for the Propeller Backpack
    ' that can be copied to other programs. The ones that are commented are already
    ' defined by the BASIC Stamp Editor and perform the same functions as they
    ' would in a DEBUG screen.
    
    'CLS           CON $00  'clear screen
    'HOME          CON $01  'home
    'CRSRXY        CON $02  'set X, Y position (X, Y follow)
    'CRSRLF        CON $03  'cursor left
    'CRSRRT        CON $04  'cursor right
    'CRSRUP        CON $05  'cursor up
    'CRSRDN        CON $06  'cursor dn
     USECLR        CON $07  'use color C (C follows)
     BS            CON $08  'backspace
    'TAB           CON $09  'tab (8 spaces per)
    'LF            CON $0A  'linefeed
    'CLREOL        CON $0B  'clear to end of line
    'CLRDN         CON $0C  'clear down (to end of window)
    'CR            CON $0D  'return
    'CRSRX         CON $0E  'set X position (X follows)
    'CRSRY         CON $0F  'set Y position (Y follows)
     DEFWIN        CON $10  'define window  W (W, Left, Top, nCols, nRows follow)
     USEWIN        CON $11  'use window W (W follows)
     DEFCLR        CON $12  'define color C (C, FG, BG follow)
     SCRLLF        CON $13  'scroll window left
     SCRLRT        CON $14  'scroll window right
     SCRLUP        CON $15  'scroll window up
     SCRLDN        CON $16  'scroll window down
     CHGCLR        CON $17  'change all colors in window to C (C follows)
     SCRSIZ        CON $1D  'set screen size (Rows, Columns follow)
     CLRW          CON $1E  'same as CLR, but can be used in strings.
     ESC           CON $1F  'escape next character C (i.e. print as-is) (C follows)
     ZERO          CON $FF  'can be used for 0, which is not allowed in strings, for command arguments
    
    '-------[ Variables ]----------------------------------------------------------
    
    i             VAR Word
    char          VAR Byte
    'U             VAR Word
    U1            VAR Word
    W             VAR Word
    '-------[ Program starts here. ]-----------------------------------------------
    
    LOW io            'Reset the Propeller Backpack
    PAUSE 500
    INPUT io
    
    PAUSE 2000        'Wait for it to come out of reset.
    
    'SEROUT io, baud, [DEFWIN, 1, 20, 2, 9, 18, USEWIN, 1, CHGCLR, 12]
    'SEROUT io, baud, [DEFCLR, 12, $AD, $0C]
    'SEROUT io, baud, [DEFWIN, 1, 20, 2, 7, 9, USEWIN, 2, CHGCLR, 13]
    'SEROUT io, baud, [DEFCLR, 12, $AD, $0C]
    'SEROUT io, baud, [DEFWIN, 1, 20, 2, 9, 18, USEWIN, 2, CHGCLR, 13]
    'SEROUT io, baud, [DEFCLR, 12, $AD, $0C]
    'FOR U =  65 TO 127
    'FOR W = 1000 TO 1050
    FOR W = 65 TO 127
    'FOR W = 65 TO 91
    'FOR W= 65 TO 99
    'FOR W = 65 TO 255
    SEROUT U1B, baud,[W] 'PIN1
    PULSOUT U1A, 4       'PIN0
    'PULSIN  U1C, 8, U1
    COUNT U1C, 4, U1     'PIN2
    SEROUT io, baud, ["___>", DEC U1, CR]
    PAUSE 1000
    SEROUT io, baud, [" ", ASC ?W,CR]
    PAUSE 350
    SEROUT io, baud, [" ", DEC W,CR]
    PAUSE 700
    NEXT
    'NEXT
    

    Now that the code can be seen I now invite comment. People who do have access to the Prop backpack and that part can try this out for themselves. Of the four inputs on the SN7423, two get connected to those pins on the BASIC Stamp, and the output goes to the input function on the Stamp. Connect an LED of your choice of color to the output of the gate. Sadly I can not supply programmed PAL chips at this time.

  • The embedded code has the Prop Backpack's setup commands commented out. The bs2 code attached to the top board is a bit different than the code you embedded.

    Can you get the Backpack to display a counting variable which the demo used?

    Do you have a version of the SN7423 code which works with a serial terminal?

    Basically, I'm asking if you've tested these two aspects of your code separately before combining them. If you have, do you still have the code to share?

    I'm curious what your overall goal is? What does the SN7423 do which you can't do with the Basic Stamp 2? Is the SN7423 used with the PAL to perform high speed tasks which couldn't be done with the Basic Stamp 2? Of course just experimenting with a chip is a perfectly fine goal but I was wondering if this chip was needed for a particular project.

  • @"Duane Degn" said:
    The embedded code has the Prop Backpack's setup commands commented out. The bs2 code attached to the top board is a bit different than the code you embedded.

    Can you get the Backpack to display a counting variable which the demo used?

    Do you have a version of the SN7423 code which works with a serial terminal?

    Basically, I'm asking if you've tested these two aspects of your code separately before combining them. If you have, do you still have the code to share?

    I'm curious what your overall goal is? What does the SN7423 do which you can't do with the Basic Stamp 2? Is the SN7423 used with the PAL to perform high speed tasks which couldn't be done with the Basic Stamp 2? Of course just experimenting with a chip is a perfectly fine goal but I was wondering if this chip was needed for a particular project.

    Hello!
    I was able to to display a counting variable using the W0 register, and it managed to show the counting of events. As for the SN7423 functions, this is something of a draw actually, mostly because I never really managed to get it to work as expected. And as for why both it is there, and even the PAL, (both now actually with a SN7460 included.), there's something going on, but I'm still not sure what.

    As for why the setup code is commented out? Good question. (Any them you mean.)

    'SEROUT io, baud, [DEFWIN, 1, 20, 2, 9, 18, USEWIN, 1, CHGCLR, 12]
    'SEROUT io, baud, [DEFCLR, 12, $AD, $0C]
    'SEROUT io, baud, [DEFWIN, 1, 20, 2, 7, 9, USEWIN, 2, CHGCLR, 13]
    'SEROUT io, baud, [DEFCLR, 12, $AD, $0C]
    'SEROUT io, baud, [DEFWIN, 1, 20, 2, 9, 18, USEWIN, 2, CHGCLR, 13]
    'SEROUT io, baud, [DEFCLR, 12, $AD, $0C]
    

    Either one tends to display the functions on the wrong background, what I wanted was white text on a black one, and combing through the well written documents that @"Phil Pilgrim (PhiPi)" didn't exactly provide me many clews. Of course I was working rather hurriedly at the time. This is a reboot of a work in progress and at the moment, I felt that posting everything, (with help, thank you @Publison and @rosco_pc and @VonSzarvas ) to make it more clear. And of course to garner more helpful comments. Oh and @"Duane Degn" you win the prize, which is for first comments. And the prize? I'm glad you asked, it is a tour of the planets involved in both the first and second Rebellion against the Empire and its forces of something else.

  • Buck RogersBuck Rogers Posts: 2,031
    edited 2021-04-29 15:41

    And I've just tried out the real reason why I brought all of that out. It did not work. I wanted to display the output of the program used to talk to a TI Calculator, the popular TI84Plus. Let's just say it did not work. And I am done here. A completely new thread with a new title will be created when I visit again the backpack.

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