MAX7219 Confusion

xanatos · 2013-06-22 09:37

I'm using the MAX7219 with a pair of 4x8 matrix LEDs (see attached datasheet).

I have the MAX7219's "digits" lines connected to the cathodes of the matrix, and the "segments" lines connected to the anodes.

Here are the relevant code sections that I am starting with, taken from Chris Savage's "Binary Digital Clock" project:

SClock          PIN     0                ' shift clock (74HC595.11, DS1302.7, MCP3202.7, MAX7219.13)
SDataIO         PIN     1                ' serial data (74HC595.14; DS1302.6 via 1k, MCP3202.6 [DO] via 1k, MCP3202.5 [DI], MAX7219.1)
M7219           PIN     5                ' MAX7219.12 CS for driving alarm panel LEDs


Decode          CON     $09              ' BCD Decode Register
Brite           CON     $0A              ' Intensity Register
Scan            CON     $0B              ' Scan Limit Register
ShutDn          CON     $0C              ' Shutdown Register (1 = On)
Test            CON     $0F              ' Display Test Mode
DecPnt          CON     %10000000        ' Decimal Point
Blank           CON     %1111            ' Blank A Digit

index           VAR     Byte             ' Loop Counter

d7219           VAR     Byte             ' Alarm Display
idxOdd          VAR     index.BIT0       ' Is Index Odd? (1 = Yes)


FOR index = 0 TO 7                      ' Initialize MAX7219
  LOOKUP index, [Scan, 7, Brite, 6, Decode, $00, ShutDn, 1], d7219
  SHIFTOUT SDataIO, SClock, MSBFIRST, [d7219]
  'IF (idxOdd = 0) THEN No_Load
  PULSOUT M7219, 5                    ' Latch The Data

No_Load:
NEXT

' -----[ Program Code ]----------------------------------------------------

Main:
    index = 1  ' This is incremented by another process
    d7219 = secs.LOWNIB                   ' Seconds (Ones Digit)
    d7219 = d7219 | DecPnt                ' Enable Decimal Point
    GOSUB AlarmPanelData
    index = index + 1                             ' Select Digit 1
    IF index > 7 THEN index = 0


' -----[ Subroutines ]---------------------------------------------------------------------------------------------------------

AlarmPanelData:
  SHIFTOUT SDataIO, SClock, MSBFIRST, [index, d7219]
  PULSOUT M7219, 5                    ' Latch Data
  RETURN

There's a lot of other stuff in there so I'm just showing the useful sections.

I've tried changing the values for the registers for NoDecode from FF to 00 (I want individual segment control, not a character map output).

The display remains BLANK no matter what I put into the initialization routine.

I'm uploading a few pictures of my wiring and the datasheet for the MAX7219. This looks like it should be simple enough - I just want to be able to light individual cells (these will indicate alarm conditions on any of my 100+ inputs) - but I am obviously doing something horribly wrong! :-) I'm thinking that once I have the setup data set correctly, I should then just be able to send my data to the 7219 in the form of the "digit" to select, and the "segments" for that digit that should be illuminated (which normally should be none... except when I'm trying to get it to light up by stuffing random test data in - but even that's not working!)

Please - help! :-)

Thanks,

Dave

Publison · 2013-06-22 09:55

Dave,

Try Jon's code for None-Decode Mode,

' Listing 1' Nuts & Volts - February 2000 - Modified for (2) cascaded MAX7219 and (2) 8x8 LED Matrix Display


' -----[ Title ]-----------------------------------------------------------
'
' File...... LEDARRAY_MOD.BS2
' Purpose... Uses the MAX7219 to drive a 8x8 LED array
' Author.... Jon Williams / Tim Gilmore
' E-mail.... jonwms@aol.com / gilmoret@us.saic.com
' Started... 06 JAN 2001
' Updated... 18 APR 2007


' {$STAMP BS2}




' -----[ Program Description ]---------------------------------------------
'
' Demonstrates the use of Maxim's MAX7219 LED display driver in the
' non-decoded mode.  In this mode, the programmer is responsible for
' sending segment (row) data for each digit (column).
'
' In this application, the MAX7219 is connected to a common-cathode LED
' array.  The array is 8 columns wide by 8 rows tall (64 LEDs).  The
' digit outputs from the MAX7219 are connect to the columns; the segment
' control lines to the rows.
'
' MAX7219 --> LED Connections:
'
'   MAX7219.2  (0) --> Col 1 (left)
'   MAX7219.11 (1) --> Col 2
'   MAX7219.6  (2) --> Col 3
'   MAX7219.7  (3) --> Col 4
'   MAX7219.3  (4) --> Col 5
'
'   MAX7219.17 (g) --> Row 1 (top)
'   MAX7219.15 (f) --> Row 2
'   MAX7219.21 (e) --> Row 3
'   MAX7219.23 (d) --> Row 4
'   MAX7219.20 (c) --> Row 5
'   MAX7219.16 (b) --> Row 6
'   MAX7219.14 (a) --> Row 7




' -----[ Revision History ]------------------------------------------------
'
' 07 JAN 2001 - Version 1
' 19 APR 2007 - Version 2 modified for (2) cascaded MAX7219 and (2) 8x8 LED Display Matrix




' -----[ I/O Definitions ]-------------------------------------------------
'
Clock     CON   0         ' shift clock to MAX7219
DPin      CON   1         ' shift data to MAX7219
Load      CON   2         '




' -----[ Constants ]-------------------------------------------------------
'
Decode    CON   $09         ' bcd decode
Intensity CON   $0A         ' brightness
Scan      CON   $0B         ' scan (column) limit
ShutDn    CON   $0C         ' shutdown (1 = on)
Test      CON   $0F         ' display test mode


NoOp      CON   $00


Yes       CON   1
No        CON   0




' -----[ Variables ]-------------------------------------------------------
'
index     VAR   Nib         ' loop counter
idxOdd    VAR   index.BIT0  ' is index odd? (1 = yes)
d7219     VAR   Byte        ' data for MAX7219


d7219A    VAR   Byte




char      VAR   Byte        ' character ee address
col       VAR   Nib         ' column value
row       VAR   Nib         ' row value
eeAddr1   VAR   Byte        ' ee pointer


eeAddr1A  VAR   Byte


eeAddr2   VAR   Byte


eeAddr2A  VAR   Byte


vScroll   VAR   Word         ' scrolling data buffer
vScrollA  VAR   Word


' -----[ EEPROM Data ]-----------------------------------------------------
'


Space       DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   0


UC_Ltr_P    DATA   000000
            DATA   000000
            DATA   111111 'P
            DATA   001001
            DATA   001001
            DATA   001001
            DATA   000110
            DATA   000000
            DATA   0


LC_Ltr_A    DATA   000000
            DATA   100000 'a
            DATA   010100
            DATA   010100
            DATA   010100
            DATA   111000
            DATA   000000
            DATA   0


LC_Ltr_R    DATA   000000
            DATA   000000
            DATA   111100 'r
            DATA   001000
            DATA   000100
            DATA   001000
            DATA   000000
            DATA   000000
            DATA   0


LC_Ltr_A2   DATA   000000
            DATA   100000 'a
            DATA   010100
            DATA   010100
            DATA   010100
            DATA   111000
            DATA   000000
            DATA   0


LC_Ltr_L    DATA   000000
            DATA   000000
            DATA   000000 'l
            DATA   000001
            DATA   111111
            DATA   000000
            DATA   000000
            DATA   00000
            DATA   0


LC_Ltr_L2   DATA   000000
            DATA   000000
            DATA   000000 'l
            DATA   000001
            DATA   111111
            DATA   000000
            DATA   000000
            DATA   00000
            DATA   0


LC_Ltr_A3   DATA   000000
            DATA   100000 'a
            DATA   010100
            DATA   010100
            DATA   010100
            DATA   111000
            DATA   000000
            DATA   0


LC_Ltr_X    DATA   000000
            DATA   000000
            DATA   000100 'x
            DATA   101000
            DATA   010000
            DATA   101000
            DATA   000100
            DATA   000000
            DATA   0




Char_Space  DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   0         ' column between characters


Char_B      DATA   000000
            DATA   000000
            DATA   111111      ' xxxxxxx
            DATA   001001      ' x..x..x
            DATA   001001      ' x..x..x
            DATA   001001      ' x..x..x
            DATA   110110      ' .xx.xx.
            DATA   000000
            DATA   0


Char_S      DATA   000000
            DATA   100110      ' .x..xx.
            DATA   001001      ' x..x..x
            DATA   001001      ' x..x..x
            DATA   001001      ' x..x..x
            DATA   110010      ' .xx..x.
            DATA   000000
            DATA   000000
            DATA   0


Char_2      DATA   000000
            DATA   000010      ' x....x.
            DATA   100001      ' xx....x
            DATA   010001      ' x.x...x
            DATA   001001      ' x..x..x
            DATA   000110      ' x...xx.
            DATA   000000
            DATA   000000


Pad         DATA   0,0,0,0,0,0,0,0
            DATA   0


Char_Space2 DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   000000
            DATA   0         ' column between characters








' -----[ Initialization ]--------------------------------------------------
'
Initialize:
  DIRL = 1               ' clock, data and load pins


   SHIFTOUT Dpin,Clock,MSBFIRST,[Scan,7,Scan,7]
   PULSOUT Load,3
   SHIFTOUT Dpin,Clock,MSBFIRST,[Intensity,7,Intensity,7]
   PULSOUT Load,3
   SHIFTOUT Dpin,Clock,MSBFIRST,[ShutDn,1,ShutDn,1]
   PULSOUT Load,3




' -----[ Main Code ]-------------------------------------------------------
'
Main:


Flash_Characters:            ' on screen, one at a time
  FOR char = 0 TO 9
    LOOKUP char,[Char_B,Char_S,Char_2,Char_Space],eeAddr1
    LOOKUP char,[UC_Ltr_P,LC_Ltr_A,LC_Ltr_R,LC_Ltr_A2,LC_Ltr_l,LC_Ltr_l2,LC_Ltr_A3, LC_Ltr_x,Char_Space],eeAddr1A
    GOSUB ShowChar
    PAUSE 1000
  NEXT




Crawl_Characters:            ' crawl on (horizontally)
  FOR eeAddr1 = Space TO Char_Space2
    GOSUB ShowChar2
  NEXT
  PAUSE 1000




Scroll_Characters:            ' scroll on (vertically)
  FOR char = 0 TO 8
    LOOKUP char,[Char_Space,Char_B,Char_S,Char_2,Char_Space,Char_Space,Char_Space,Char_Space,Char_Space],eeAddr1
    LOOKUP char,[Char_B,Char_S,Char_2,Char_Space],eeAddr2
    LOOKUP char,[Char_Space,UC_Ltr_P,LC_Ltr_A,LC_Ltr_R,LC_Ltr_A2,LC_Ltr_l,LC_Ltr_l2,LC_Ltr_A3, LC_Ltr_x],eeAddr1A
    LOOKUP char,[UC_Ltr_P,LC_Ltr_A,LC_Ltr_R,LC_Ltr_A2,LC_Ltr_l,LC_Ltr_l2,LC_Ltr_A3, LC_Ltr_x,Char_Space],eeAddr2A
    FOR row = 1 TO 8
      FOR col = 1 TO 8
        READ (eeAddr1 + col - 1),vScroll.LOWBYTE
        READ (eeAddr2 + col - 1),vScroll.HIGHBYTE
        READ (eeAddr1A + col - 1),vScrollA.LOWBYTE
        READ (eeAddr2A + col - 1),vScrollA.HIGHBYTE
        d7219 = vScroll >> (row - 1)   ' get "frame"
        d7219A = vScrollA >> (row - 1)   ' get "frame"
        SHIFTOUT Dpin,Clock,MSBFIRST,[col,d7219A,col,d7219]
        PULSOUT Load,3
      NEXT
      PAUSE 100
    NEXT
  NEXT
  PAUSE 1000


  GOTO Main
  END




' -----[ Subroutines ]-----------------------------------------------------
'
ShowChar:
  FOR col = 1 TO 8            ' character is 8 columns wide
    READ (eeAddr1 + col - 1),d7219      ' read column data from EEPROM
    READ (eeAddr1A + col - 1),d7219A
    SHIFTOUT Dpin,Clock,MSBFIRST,[col,d7219A,col,d7219]
    PULSOUT Load,3
  NEXT
  RETURN




  ShowChar2:
  FOR col = 1 TO 8            ' character is 8 columns wide
    READ (eeAddr1 + col - 1),d7219      ' read column data from EEPROM
    SHIFTOUT Dpin,Clock,MSBFIRST,[col,0,col,d7219]
    PULSOUT Load,3
  NEXT
  FOR col = 1 TO 8            ' character is 8 columns wide
    READ (eeAddr1 + col - 9),d7219      ' read column data from EEPROM
    SHIFTOUT Dpin,Clock,MSBFIRST,[col,d7219,col,0]
    PULSOUT Load,3
  NEXT
  RETURN

xanatos · 2013-06-22 11:33

Problem solved. If all else fails and you start to think you're losing it... change the chip. Not sure if I cooked the first one trying to send it configuration data that sent it to Titan or something, or if I somehow shorted something, but the chip itself was just dead. Dropped a new chip in, powered up, and there, before my wondering eyes did appear.... the display I expected! Having all sorts of fun now making cool shifting patterns, before the work begins of creating the correspondence table to figure out how to display multiple individual cells when/if one or more sensors goes into an alarm threshold...

THANKS GUYS!

Dave

MAX7219 Confusion

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