weird problem with dot matrix and shift register

[Darrel Taylor]

I think you just need to "Blank" the rows before changing the Column data, then turn the next row on.

Try it like this ...

FOR CNTR2 = 0 TO 100
  FOR CNTR1 = 0 TO 7
    STRB = 0
    COL = COLVAR[CNTR1]^255
    SHIFTOUT DAT,CLK,0,[COL]
    PORTB = 0                   ; blank all Rows
    STRB = 1                    ; latch the data
    PORTB = DCD CNTR1           ; turn on next Row

    PAUSE 2
  NEXT CNTR1
NEXT CNTR2