Shifting to shift registers

george miyagi · 2005-07-03 04:19

Hi
i'm using the Max7219, well actaully 6 of them. But for the life of me, I can't work out how to shift more than 8x8 bits to them at once. How would i shift out a larger graphic to them?

Jon Williams · 2005-07-03 13:29

Just put the values you want to send in the output field.· Let's say you want to send eight bytes: data1..data8....

· SHIFTOUT Dpin, Cpin, MSBFIRST, [noparse][[/noparse]data1, data2, data3, data4, data5, data6, data7, data8]

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Jon Williams
Applications Engineer, Parallax

george miyagi · 2005-07-03 16:05

thanks. I got it working to a certain degree. if i manually put the values into EEprom.
however, I'm receiving the values via SERIN, and this is where is gets confusing....

Jon Williams · 2005-07-03 16:12

You may need to post your code in order for us to help. Keep in mind that SHIFTOUT does not allow you to use the STR modifier like SEROUT, so you've got to spell out your bytes (even if in an array) like I did above. STR is not allowed in SHIFTOUT because the \ symbol is used to indicate the number of bits sent, where in SEROUT it is used for bytes (because SEROUT always sends eight-bit values, SHIFTOUT can do anything from 1 to 16 [noparse][[/noparse]default is 8]).

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Jon Williams
Applications Engineer, Parallax

george miyagi · 2005-07-03 16:24

ok, thanks.
forgive the messy code, just trying to get it to work.


progPin CON 16 ' The programming PIN
ledCmd VAR BYTE
serStr VAR BYTE(10)
d7219         VAR BYTE   
d7219_b         VAR BYTE 
d7219_c         VAR BYTE  
d7219_d         VAR BYTE 
d7219_e         VAR BYTE  
d7219_f        VAR BYTE    

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

Yes           CON 1
No            CON 0


'==========Variables=========================

index         VAR NIB                                    ' loop counter
idxOdd        VAR index.BIT0                             ' is index odd? (1 = yes)
                                 ' data for MAX7219
char          VAR BYTE                                   ' character ee address
col           VAR NIB                                    ' column value
row           VAR NIB                                    ' row value
eeAddr1       VAR BYTE                                   ' ee pointer
eeAddr2       VAR BYTE
vScroll       VAR WORD                                   ' scrolling data buffer
'inBlips       VAR WORD 


'=====EEPROM Data=============================

'=========Initialization======================================
'++++++This is edited code++++
'++++ LOOKUP index,[noparse][[/noparse]Scan,7,Intensity,7,ShutDn,1],d7219 +++++
'===============================================================
LOW Load
Initialize:
  DIRL = %111                                            ' clock, data and load pins
 FOR index = 0 TO 5
    LOOKUP index,[noparse][[/noparse]Scan,7,Intensity,7,ShutDn,1],d7219
    SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]d7219]
    IF idxOdd = No THEN NoLoad
    PULSOUT Load,3                                       ' load parameter
  NoLoad:
  NEXT

'DATA 

Main:

get_Data:
' SEROUT progPin, 84,  ' SEND the serial DATA
      FOR col = 1 TO 8
SERIN progPin, 84, [noparse][[/noparse]WAIT ("*"), BIN d7219] ' wait for Comm
SEROUT progPin, 84,  ' SEND confirmation
SERIN progPin, 84, [noparse][[/noparse]WAIT ("*"), BIN d7219_b] ' wait for Comm        
SEROUT progPin, 84,  ' SEND confirmation
SERIN progPin, 84, [noparse][[/noparse]WAIT ("*"), BIN d7219_c] ' wait for Comm        
SEROUT progPin, 84,  ' SEND confirmation
SERIN progPin, 84, [noparse][[/noparse]WAIT ("*"), BIN d7219_d] ' wait for Comm        
SEROUT progPin, 84,  ' SEND confirmation
SERIN progPin, 84, [noparse][[/noparse]WAIT ("*"), BIN d7219_e] ' wait for Comm        
SEROUT progPin, 84,  ' SEND confirmation
SERIN progPin, 84, [noparse][[/noparse]WAIT ("*"), BIN d7219_f] ' wait for Comm        
SEROUT progPin, 84,  ' SEND confirmation
    
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_f]
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_e]
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_d]
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_c]
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_b]
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219]
PULSOUT Load,3
 NEXT

  PAUSE 100

GOTO Main

george miyagi · 2005-07-03 16:30

and this is the code that's working 'maniually'




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

Yes           CON 1
No            CON 0


'==========Variables=========================

index         VAR NIB                                    ' loop counter
idxOdd        VAR index.BIT0                             ' is index odd? (1 = yes)
d7219         VAR BYTE   
d7219_b         VAR BYTE 
d7219_c         VAR BYTE  
d7219_d         VAR BYTE 
d7219_e         VAR BYTE  
d7219_f        VAR BYTE                                   ' data for MAX7219
char          VAR BYTE                                   ' character ee address
col           VAR NIB                                    ' column value
row           VAR NIB                                    ' row value
eeAddr1       VAR BYTE                                   ' ee pointer
eeAddr2       VAR BYTE
eeAddr3       VAR BYTE
eeAddr4       VAR BYTE
eeAddr5       VAR BYTE
eeAddr6       VAR BYTE
vScroll       VAR WORD                                   ' scrolling data buffer



'=====EEPROM Data=============================

                                   ' column between characters

Char_0        DATA %00000000
              DATA %00000000
              DATA %00000000
              DATA %00000000
              DATA %00111110
DATA %00100010
DATA %00000100
DATA %00011100 
              DATA 0

Char_1        DATA %00000000
              DATA %00000000
              DATA %00000000
              DATA %00000000
              DATA %00111000
              DATA %01000100
DATA %01000100   
DATA %10101010
DATA 0

Char_2    DATA %00000000
             DATA %00000000
        DATA %00000000
        DATA %00000000
        DATA %00111000
DATA %01000100
DATA %01000100
DATA %10101010

Char_3    DATA %00010000
        DATA %00100010
        DATA %00111110
        DATA %00000000
        DATA %00000000
DATA %00000000
DATA %00000000
DATA %00000000

Char_4    DATA %01000100
        DATA %01000100
        DATA %00111000
        DATA %00000000
        DATA %00000000
DATA %00000000
DATA %00000000
DATA %00000000

Char_5    DATA %01000100
              DATA %01000100
              DATA %00111000
              DATA %00000000
              DATA %00000000
DATA %00000000
DATA %00000000
DATA %00000000
              DATA 0  
'=========Initialization======================================

Initialize:
  DIRL = %111                                            ' clock, data and load pins

  FOR index = 0 TO 5
    LOOKUP index,[noparse][[/noparse]Scan,7,Intensity,7,ShutDn,1],d7219
    SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]d7219]


    IF idxOdd = No THEN NoLoad
    PULSOUT Load,3                                       ' load parameter
  NoLoad:
  NEXT

Main:


  FOR char = 0 TO 4
    LOOKUP 0,[noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5],eeAddr1
 LOOKUP 1,[noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5],eeAddr2
LOOKUP 2, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5],eeAddr3
LOOKUP 3, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5],eeAddr4
LOOKUP 4, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5],eeAddr5
LOOKUP 5, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5],eeAddr6
    GOSUB ShowChar
    PAUSE 1000
  NEXT



END 

'=================================================================================

ShowChar:
  FOR col = 1 TO 8                                     
    READ (eeAddr1 + col - 1),d7219   
READ (eeAddr2 + col - 1),d7219_b  
READ (eeAddr3 + col - 1),d7219_c    
READ (eeAddr4 + col - 1),d7219_d    
READ (eeAddr5 + col - 1),d7219_e   
READ (eeAddr6 + col - 1),d7219_f                   
 SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_f]
  SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_e]
 SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_d]
  SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_c]
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219_b]
    SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219]

 PULSOUT Load,3
  NEXT
  RETURN

Jon Williams · 2005-07-03 17:01

There are a few things you can simplify:

Q: Do you have control over the transmitting end?· If yes, just use one sync character and send a single byte (the value) for each position instead of the eight-byte binary string (this will speed up comms significantly).· Then you can do this:

· SERIN ProgPin, Baud, [noparse][[/noparse]WAIT ("*"), STR d7219\6]

(Note: You should NOT hardcode baud values -- put them into a constant.· Trust me on this.)· If you're sending the data as binary strings to avoid a conflict with the sync character, change to HEX2 format and do it like this:

· SERIN ProgPin, Baud, [noparse][[/noparse]WAIT ("*"), HEX2 d7219(0), HEX2 d7219(1), HEX2 d7219(2),··· ' <
························HEX2 d7219(3), HEX2 d7219(4), HEX2 d7219(5)]

That eliminates six bytes per item.· I've also put the 7219 data into an array to simplify other processes.

In your second program, this section of code:

· FOR char = 0 TO 4
·· ·LOOKUP 0, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5], eeAddr1
·· ·LOOKUP 1, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5], eeAddr2
·· ·LOOKUP 2, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5], eeAddr3
·· ·LOOKUP 3, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5], eeAddr4
·· ·LOOKUP 4, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5], eeAddr5
·· ·LOOKUP 5, [noparse][[/noparse]Char_0,Char_1,Char_2,Char_3,Char_4,Char_5], eeAddr6
·· ·GOSUB ShowChar
··· PAUSE 1000
· NEXT

... is a big waste of space since you're always using a fixed index for LOOKUP.· Is that what you meant to do?· And if your EE defintiions are of a fixed size and place in order, you can simply calculate an offset address.· This line of code will take the value in "theChar" and calculate the address for it:

· eeAddr = Char_0 + (theChar * 9)

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Jon Williams
Applications Engineer, Parallax

george miyagi · 2005-07-03 18:31

hi thanks for the swift reply.
yes, i do have control over the transmitting end. perhaps it would've been helpful to explain what i'm doing. i am using Processing, ie. semi-Java, taking an image, converting it to binary to represent the black and white (on and off) states. That's why I'm using binary on both sides. So I'm only ever sending 1's and 0's. I will probably convert these to decimal later on, but at moment just trying to get it working.

so i've modified the code slightly, but it's still not working. Should i be sending all 64 bits of one 8x8 matrix, or should it be done as it is now, row for row?


progPin CON 16 ' The programming PIN
ledCmd VAR BYTE
serStr VAR BYTE(10)
d7219         VAR BYTE   
d7219_b         VAR BYTE 
d7219_c         VAR BYTE  
d7219_d         VAR BYTE 
d7219_e         VAR BYTE  
d7219_f        VAR BYTE    
Baud CON 84
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

Yes           CON 1
No            CON 0


'==========Variables=========================

index         VAR NIB                                    ' loop counter
idxOdd        VAR index.BIT0                             ' is index odd? (1 = yes)
                                 ' data for MAX7219
char          VAR BYTE                                   ' character ee address
col           VAR NIB                                    ' column value
row           VAR NIB                                    ' row value
eeAddr1       VAR BYTE                                   ' ee pointer
eeAddr2       VAR BYTE
vScroll       VAR WORD                                   ' scrolling data buffer


'=========Initialization======================================

LOW Load
Initialize:
  DIRL = %111                                            ' clock, data and load pins
 FOR index = 0 TO 5
    LOOKUP index,[noparse][[/noparse]Scan,7,Intensity,7,ShutDn,1],d7219
    SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]d7219]
    IF idxOdd = No THEN NoLoad
    PULSOUT Load,3                                       ' load parameter
  NoLoad:
  NEXT

'DATA 

Main:

get_Data:
FOR col = 1 TO 8
SERIN ProgPin, Baud, [noparse][[/noparse]WAIT ("*"), BIN d7219(0), BIN d7219(1), BIN d7219(2), BIN d7219(3), BIN d7219(4), BIN d7219(5)]      
SEROUT progPin, Baud,  ' SEND confirmation
FOR row = 0 TO 5   
SHIFTOUT Dpin,Clock,MSBFIRST,[noparse][[/noparse]col,d7219(row)]
NEXT
PULSOUT Load,3
 NEXT

  PAUSE 100

GOTO Main

Post Edited (george miyagi) : 7/3/2005 6:54:30 PM GMT

Shifting to shift registers

Comments