5x7 LED Matrix Scrolling Display


Closed Thread
Results 1 to 19 of 19

Hybrid View

  1. #1
    Join Date
    Jul 2003
    Posts
    2,405


    Did you find this post helpful? Yes | No

    Default

    Dang Joe, you're getting good at posting here. The scrolling text thing was pretty cool..:}

    Roy;

    Don't get upset by what people post here in response to something you're looking for that's relatively complex, especially when the link you provide to a schematic isn't available, and no one can download a copy to look at - in an attempt to help you.

    Skimask & Patrick Pending both assumed, by your stating
    First - I am new to PBP and Pic Chips
    that you were a complete newbie, and had no idea how to get started even blinking an LED.

    I know this may sound harsh, but it really is excellent advice. Assuming someone's just getting started. Just blinking an LED tells you quite a lot beleive it or not.

    1. Your programmer is working as expected.
    2. Your config settings are probably OK.
    3. Your oscillator is working.
    4. The circuit you have assembled is probably OK.
    5. Your compiler is working.

    And several other things. It's not that anyone here is trying to give you a hard time - they just want to make sure newbies understand a few basic proceedures before they spend a boat-load of time trying to help them figure out something more complex.

    If you show some attempt at getting this to work, I.E. you have a simple example of code you have put together that doesn't work, I really think the folks here will jump in head-over-heels to help you get it sorted out.

    There's an amazing amount of talent here, and most will do back-flips to help someone out, but they will normally want to see at least a modest effort on the part of the person submitting a request for help first. Not just - here's what I want to do - here's a schematic, give me some code to get started.

    I think if you can at least post a schematic, and be specific about what you're looking to do, 'maybe with a note: I have no idea how to get started' - you'll find this forum better than any other you can find.

    I have also gone through lessons using PicAxe chips and was directed to PBasic & Pics by Reynold's Electronics as a means to save money - not true.
    Which part of this is not true?

    A PIC18F2431 costs only $7.68 in qty of 1, and can run rings around the fastest Stamp, and has built in hardware peripherals like timers, counters, hardware PWM, USART, I2C, SPI, motion control module, power control PWM, and a host of other features.

    What would it cost to add these peripherals to a $50.00 BASIC Stamp module with zero built-in peripherals? Now figure that times 10 or more projects.

    BASIC Stamps are very cool, but a $3.00 PIC can replace one, and it has a ton of built-in hardware peripherals that would cost a lot more to add to any Stamp project. And you're not yanking that $50.00 Stamp module out of every project for the next once since a PIC is much less expensive, and can be left there.

    If you're serious about learning this stuff, stick around. There's a lot of talent here just waiting to help....;o}
    Regards,

    -Bruce
    tech at rentron.com
    http://www.rentron.com

  2. #2
    Join Date
    Mar 2008
    Posts
    5


    Did you find this post helpful? Yes | No

    Default 5x7 Display

    Sorry for the hasty remarks. I will dig more and see what I can find online regarding using 74HC425 chips and Pic Chips to control a string of LEDs.

  3. #3
    Join Date
    Aug 2006
    Location
    Look, behind you.
    Posts
    2,818


    Did you find this post helpful? Yes | No

    Default

    Quote Originally Posted by roycarlson View Post
    Sorry for the hasty remarks. I will dig more and see what I can find online regarding using 74HC425 chips and Pic Chips to control a string of LEDs.
    Good, now we have put all this silliness behind us, Which PIC are you going to use, what kind of oscillator will you use, internal or crystal, what osc frequency, can you post the schematic ?
    If you do not believe in MAGIC, Consider how currency has value simply by printing it, and is then traded for real assets.
    .
    Gold is the money of kings, silver is the money of gentlemen, barter is the money of peasants - but debt is the money of slaves
    .
    There simply is no "Happy Spam" If you do it you will disappear from this forum.

  4. #4


    Did you find this post helpful? Yes | No

    Default

    Hi Roy,

    I had hoped to add a little bit of background about myself when I posted my reply, but my 7-year old was bugging me at the time so it had to be brief.

    I started programming PICs about a year ago, so I still consider myself a relative newbie - I'm just a little bit further along the path than you are. I have started a number of projects that I have had to temporarily abandon while my programming skills catch up with my expectations. Initially, I did not take my own advice and started in the middle, working backwards to try and fill in the gaps. I can tell you, from first-hand experience, that this is not the best way to do it. Working this way is frustrating, as the simplest of mistakes (which would be obvious to those who had started at the beginning) can stop your project working.

    In case there still remains any doubt let me say that it was good, honest, friendly advice from someone who has been where you have - and I don't mean Milton Keynes ;-)

    All the best,
    Pat. Pending

  5. #5
    Join Date
    May 2008
    Location
    Florida
    Posts
    64


    Did you find this post helpful? Yes | No

    Default Getting started

    Quote Originally Posted by roycarlson View Post
    Sorry for the hasty remarks. I will dig more and see what I can find online regarding using 74HC425 chips and Pic Chips to control a string of LEDs.
    I am very new here myself. I will share what I have found over the years and in my short time here.

    People don't mind helping, but they hate doing it for you.

    The link you provided is dead, you have some 'kit' you bought and no documentation for it. You are not sure what PIC you want to use.

    You are requesting help, with no information to start with the standard help around here is 'Blinky'.

    I program for a living and buld electronics as a hobby.
    When I started I bought PBP, 2 development boards and a hand full of PICs. I browsed this site and read a LOT of posts. Once I thought I might have enough info, I cracked open the ugly green book and the manual for the development board.

    I tried 'Blinky' and guess what it didn't work much to my surprise. Came back here and searched for all the blinky posts. Oooops found out I had not configured the PIC right.
    To make matters worse I had two development boards and they both work differently and I also have to different compilers I will not even begin to talk about those.

    After Blinky and then Blink 2 LEDs, and so on I worked my way up to try the LCD. I spent hours trying everything I could and at last broke down and posted to the forum. Posted my code and which development board I was using and described my problem.

    If you locate that post you will find hints as to what my problem was, but I had to work it out on my own. The answer was there just not spelled out in so many words.

    The only way a person can learn is to crawl in and get up to their necks in it.

    Read this forum and count how many posts begin; I need code for my class project that is due tomorrow. Help plz.

    At times it can get a little chilly around here, but the members on this forum go the extra mile for people who are really trying.

    Step into my palor said the spider to the fly. Go ahead Roy you stuck your head in, go for broke.

    p.s. I decided on a PIC16F887 to start with it has just about everything you can cram into a chip.

  6. #6
    Join Date
    Aug 2006
    Location
    Look, behind you.
    Posts
    2,818


    Did you find this post helpful? Yes | No

    Default

    Quote Originally Posted by manwolf View Post

    p.s. I decided on a PIC16F887 to start with it has just about everything you can cram into a chip.
    #1 reason most PIC books use the PIC16F84, old Grandpa has near nothing to get in the way of a newbie's success.
    Patrick Pending, I am into this 2 years this month, still fumbling and learning, still putting in "temporary blinky code" in my projects.
    If you do not believe in MAGIC, Consider how currency has value simply by printing it, and is then traded for real assets.
    .
    Gold is the money of kings, silver is the money of gentlemen, barter is the money of peasants - but debt is the money of slaves
    .
    There simply is no "Happy Spam" If you do it you will disappear from this forum.

  7. #7


    Did you find this post helpful? Yes | No

    Default

    Yes Joe, I agree. The 16F84 is plain Vanilla and a good place to start. You can of course get PICs with more functions, more code space, more I/O pins and all that at a cheaper price, but that is not necessarily what a beginner needs. The additional functions mean additional complexity either in setting them up or even just disabling the functions your not using.

    Today I was using (the humble) 12F509 for the first time. I had RTFM and subsequently set weak pull-ups and configured the TRIS register for the appropriate I/O. But, I just couldn't understand why my simple program wasn't producing an output on GP2. So, I added a temporary blinky on another pin and that was working. I redirected the output to that pin and my program was definitely working. I knew it had to be down to configuration. It was time to RTFM (again!) or more accurately RTFDS (...Data Sheet).

    And there it was a small note on page 24 of 98:

    <i>Note: If the T0CS bit is set to ‘1’, it will override
    the TRIS function on the T0CKI pin.</i>

    Bingo! I disabled TOCS with OPTION_REG.5 = 0
    My program was now working properly

    To get to the point I was trying to make - it is precisely these sort of quirks that stop a newcomer dead in their tracks, with a little bit more experience you can find your way round them. So I think a "plain Vanilla" chip is best to start with, get your feet wet, then move on to something slightly more advanced.
    Pat. Pending

  8. #8
    Join Date
    Mar 2008
    Posts
    5


    Did you find this post helpful? Yes | No

    Default Thanks Guys

    I guess I was more fustrated at the ebay vendor for not providing the code or schematic.

    If these is a way to paste a picture here I would. I have a few 16F887 and 16F877 40 Pin Pics laying around to use. I am trying to figure out how the board has the two 74HC425s configured as it appears it is using Pic Pins 2-5, 7-11 and 15-25 for the columns via the transistors (20) to the LED columns.

    It also looks like pins 33-39 are connected to pins 2-8 of the 74HC425 chip #1 while there is crossover to the second HC425 chip via pin 2 to pin 18 on chip #2.

    The LED Matrix have red or green outputs which are controlled by toggle switch. And it appears swith 29 & 31 are conected to ground via push button switches.

    ** Is there a way to paste the photo of the board?
    Last edited by roycarlson; - 4th August 2008 at 03:35.

  9. #9
    Join Date
    Nov 2003
    Location
    Wellton, U.S.A.
    Posts
    5,924


    Did you find this post helpful? Yes | No

    Default

    If these is a way to paste a picture here I would.
    Have a look at this thread. Talks about inline pictures. Or just do an attachment.
    http://www.picbasic.co.uk/forum/showthread.php?t=9156
    Dave
    Always wear safety glasses while programming.

Similar Threads

  1. Conway's Game Of Life
    By wellyboot in forum mel PIC BASIC Pro
    Replies: 45
    Last Post: - 28th May 2020, 06:14
  2. 8x8 Scrolling LED display (Simple example)
    By wellyboot in forum Code Examples
    Replies: 68
    Last Post: - 11th July 2013, 05:03
  3. Replies: 2
    Last Post: - 14th July 2008, 22:11
  4. 245 Led Matrix Display (as constructed by Magu)
    By magu in forum Code Examples
    Replies: 11
    Last Post: - 29th June 2007, 00:07
  5. LCD will not start
    By btaylor in forum mel PIC BASIC Pro
    Replies: 49
    Last Post: - 24th May 2007, 02:30

Members who have read this thread : 0

You do not have permission to view the list of names.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts