In SX Microcontrollers, SX/B Compiler and SX-Key Tool, tdg8934 wrote:

Thanks PJ. It worked well for the first phase in this application. 

I did not have enough current using my Parallax Professional Development Board (PDB) so this is why I was not seeing the correct output. /OE on each of the (10) A6821 is used to control the color (red, green or yellow) of each of the (5) 8x8 LED Matrix Modules. When I wired the SX-28 on a separate solderless breadboard and connected the external display board with A6821s to the solderless breadboard, I used my big 5vdc 20A power supply and then saw the LEDs come on correctly. I wrote a change to turn all the LEDs on and measured 2.3 Amps of current draw (then changed it back to the normal program). Before on the PDB, the power supply is only 1 Amp I beleive, and the LEDs were either the wrong color or not on at all on some of the LED Matrix Modules. The lack of current was affecting the /OE lines and probably more. 

Since the (40) columns are controlled by Clock, DataIn and Latch to the (10) A6821s, this is where I thought the scanning routine should be for marquee scrolling (right to left). The (8) rows (up to down) would then have the data message characters READ in. 

Anyway, I'm sure I'll have more questions...

Thanks again.

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