Problem: Issues implementing double indirect addressing for shift register data in assembly
Solution: Binary decision tree created to locate the correct data byte for each SpiStep value until the indirect addressing code could be implemented.
Problem: Running out of memory to store forth words (error accessing address $8000)
Solution: Optimise code base, not add unnecessary functions, avoid redefining too many between resets during development
Problem: Accessing pins within the DMD’s ribbon cable for both the 68HC11 and Arduino
Solution: Build an Arduino adapter/breakout board based on the adapter schematic available online
Problem: Keeping connections tidy and avoiding signal noise
Solution: Create an adapter to fit directly onto the 68HC11 development board pin header and convert to DMD ribbon cable
Problem: Data inverted when displayed on the DMD, possibly due to the shift registers sinking current and not supplying as was assumed.
Solution: Add an extra assembly language command to perform an Exclusive OR (EOR) on the display data before sending it to the SPI subsystem’s data register.
-1 # EORB SPDR STAB