+ Reply to Thread
Results 1 to 4 of 4
  1. #1
    Join Date
    Feb 2013
    Posts
    546

    Default 4x MAX7219 dot matrix modules, daisy chained, usable with PBP

    Hello, there are a lot of modules, containing 4x MAX7219, which are daisy chained, and each of them drives 8x8 led matrix, like this: https://www.ebay.com/itm/MAX7219-Blue-led-matrix-MCU-control-LED-Display-module-for-Arduino-Raspbe-JBM/264335324017

    I want to drive them with PBP, and as I learned from this app note: https://www.maximintegrated.com/en/app-notes/index.mvp/id/3947 when they are daisy chained with all pins, I have to send complete set of data in sequence. I mean, first I send data for 1st module (whole batch, including brightness, decode mode, etc) and when I send it again, 2nd module receives it, then 3rd module and so on, correct?



  2. #2
    Join Date
    Nov 2003
    Location
    Greece
    Posts
    2,915

    Default Re: 4x MAX7219 dot matrix modules, daisy chained, usable with PBP

    Yes, you have to send 16 bits x number of chips in the chain.

    Clock and CS\-Load is common for all chips

    Send the bits while CS\-Load is low and at the end set CS\-Load to high to latch the data to the chips.

    Ioannis

  3. #3
    Join Date
    Feb 2013
    Posts
    546

    Default Re: 4x MAX7219 dot matrix modules, daisy chained, usable with PBP

    So say I want to directly send something to chip #3, but I can't, right? have to update whole daisy chain at same time?

  4. #4
    Join Date
    Nov 2003
    Location
    Greece
    Posts
    2,915

    Default Re: 4x MAX7219 dot matrix modules, daisy chained, usable with PBP

    Well, you can have seperate lines for the CS\-Load from the PIC and while sending the complete set of bits, select only the CS\-Load of the specific chip. The others will not latch the data already in their shift register.

    But as you can understand, the data is shifted-in and shifted out from each chip in the chain, so have to pass through.

    Ioannis

Similar Threads

  1. Sure Electronics 0832 Dot Matrix Display
    By wellyboot in forum Code Examples
    Replies: 10
    Last Post: - 2nd January 2013, 19:50
  2. Sure Electronics Dot Matrix Display
    By Bill Legge in forum mel PIC BASIC Pro
    Replies: 3
    Last Post: - 6th May 2010, 13:30
  3. PbP usable releases ???
    By Acetronics2 in forum General
    Replies: 2
    Last Post: - 15th July 2009, 13:12
  4. Flashing!! LED Dot matrix problem
    By chai98a in forum mel PIC BASIC Pro
    Replies: 3
    Last Post: - 4th December 2006, 09:45
  5. 4x16 Dot Matrix LCD control is possible?
    By muskut in forum mel PIC BASIC Pro
    Replies: 1
    Last Post: - 1st September 2005, 09:56

Members who have read this thread : 12

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