Prop Backpack being revisited
Buck Rogers
Posts: 2,185
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 'NEXTNow 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.
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.)
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.
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.