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Video output and the QuickStart and an existing display device — Parallax Forums

Video output and the QuickStart and an existing display device

Buck RogersBuck Rogers Posts: 2,185
edited 2013-11-30 21:24 in General Discussion
Hello!
I bought this critter http://www.adafruit.com/products/910 originally for my Raspberry Pi but actually ran out of momentum for making it work there. Naturally with my restart of interest with the Propeller family, according to the board its wearing a PX832A one, its a QuickStart one of course.

I then explored the OBEX for the video output ones that I knew of, and selected a batch. Looking at the code for the 1Pin one, it seemed to be a good idea, but will it run properly on the QS? Or is it aimed at any of the other boards and chips?

My original idea was to move my ideas concerning data manipulation and displaying it from the LCD Display #27977RT which worked well enough when attached to the BS2 on the board I have, to a Prop such as that one, and the display I described there.

Next one up, when trying to use the search box I came across one calling itself PropBASIC, can such an entity be leveraged to accept the meanings behind what I convinced or confused the BS2 to do with the selected PAL chip and the character display?

Please understand folks I do not expect an immediate response to all of that, in fact I'd greatly prefer it to take some time.

Eventually by the way if that idea does work, it will be, ah, spun up, to one of the larger displays in the same family. There are three of them incidentally. :blank:

Comments

  • ercoerco Posts: 20,256
    edited 2013-11-30 20:50
    The quickest way to get your LCD-style data to show up on a video monitor is probably the Propeller Backpack, which comes preprogrammed and ready to go. Nothing a QS board couldn't do with some fiddling, though.

    http://www.parallax.com/product/28327
  • Mike GreenMike Green Posts: 23,101
    edited 2013-11-30 20:53
    Yes, the QS board can use the 1-pin video driver and I've used that with a similar video display. You just need the appropriate resistor(s). I've used the 470pF capacitor and the 191 and 124 Ohm resistors as shown starred in the source code comments.
  • Buck RogersBuck Rogers Posts: 2,185
    edited 2013-11-30 21:02
    erco wrote: »
    The quickest way to get your LCD-style data to show up on a video monitor is probably the Propeller Backpack, which comes preprogrammed and ready to go. Nothing a QS board couldn't do with some fiddling, though.

    http://www.parallax.com/product/28327

    Hello!
    Thank you erco. As it happens that was my first idea, even before the RasPi became available over here, and even before buying that LCD display. I believe I was trying out much of the same walk arounds with the PAL chips with the BASIC Stamp pair that I had already.

    Next of course will be obtaining one of those, but for the Stamp board that's here.......


    For the Prop directly..... Ideas are taking shape.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-11-30 21:08
    I haven't used the 1-pin driver myself but doesn't it limit the colors you can get from the Prop?

    I've used the resistor values shown in the Demo board schematic on a bunch of different Propeller board. It always kind of seems like magic when it works so easily.

    Be aware a lot of video drivers use a lot of the Propeller's RAM.

    There used to be a fun accelerometer demo in the Propeller Tool library. It displayed a box that would change orientation on a TV screen (based on the accelerometer's orientation). I tried to modify the program to add some other feature and I soon ran out of memory.

    I believe there are all sort of tricks one can do to reduce the memory cost of video but I often just cheat and use a second Propeller as a video slave when I want to add video to a large program.

    BTW, What are the "PAL chips" you keep referring to?
  • Buck RogersBuck Rogers Posts: 2,185
    edited 2013-11-30 21:09
    Mike Green wrote: »
    Yes, the QS board can use the 1-pin video driver and I've used that with a similar video display. You just need the appropriate resistor(s). I've used the 470pF capacitor and the 191 and 124 Ohm resistors as shown starred in the source code comments.


    Hello!
    Okay Mike good to know, and thank you. That means as the week works itself out, I'll check to see if I have the same resistor parts in stock, I think I've got the capacitor some place though. But those resistors strike me as a case of the odd man out. (Twice even.)


    Once I get the demo working, then I've got a good ways to go regarding the SPIN and ASM code for the programming I'll need to tag the selected PAL chip and thence back to the QS and of course onto the display.


    Oddly enough that's what I was running towards much earlier, when the Backpack first turned up, and an interesting discussion regarding the development of it surfaced. :cat: It would seem that one of my cats has reminded me of all of that........
  • Buck RogersBuck Rogers Posts: 2,185
    edited 2013-11-30 21:24
    Duane Degn wrote: »
    I haven't used the 1-pin driver myself but doesn't it limit the colors you can get from the Prop?

    I've used the resistor values shown in the Demo board schematic on a bunch of different Propeller board. It always kind of seems like magic when it works so easily.

    Be aware a lot of video drivers use a lot of the Propeller's RAM.

    There used to be a fun accelerometer demo in the Propeller Tool library. It displayed a box that would change orientation on a TV screen (based on the accelerometer's orientation). I tried to modify the program to add some other feature and I soon ran out of memory.

    I believe there are all sort of tricks one can do to reduce the memory cost of video but I often just cheat and use a second Propeller as a video slave when I want to add video to a large program.

    BTW, What are the "PAL chips" you keep referring to?


    Hello!
    Holy socks!
    That was just written while I was writing my two responses. Lets see how I can best answer everything.

    When I got my first Prop board at the Maker Faire when it first landed at the NY Hall of Science some three years ago, I had explored it briefly, but never got as far as applying it. I was going to try out the 1-pin driver one, when I found that it had disappeared on me, and took all of the other Parallax items I had collected, including both Basic Stamps.

    The Stamp board I have now, and the QS are my return to this world.

    Now to best answer your question regarding the PAL chips. PAL stands for Programmable Array Logic. It was invented by Monolithic Memories approximately thirty-five years ago. One of their favorite uses was being programmed to become memory management units in several species of home computer. They were also programmed to do much of that for add on boards for the original families of the IBM PC.

    Users also used them for a variety of other uses.

    But this WikiPedia article does a much better job then I, http://en.wikipedia.org/wiki/Programmable_Array_Logic it also includes photos and some other assorted things.

    Now sadly they are a part of technology's history. And are typically used by people like myself who need that kind of technology for the precise computational methods that ordinary TTL logic can do versus the extremely weird methods that the others not discussed here do. (The fact that Parallax makes an Arduino BOE is something I find ironic. And I even own one.)

    Incidentally I'm inclined to answer as many questions about those things as you want to ask, but in a different thread.

    Regarding your comments on video and the Prop, at the moment I've not even tried out the demo let alone coded something based on the existing code samples...... I'll know more after the demo works. All I basically need to see on the screen is ordinary text. No colors.
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