Quote Originally Posted by flotulopex View Post
First, the "need for speed" is due to the display refresh rate. The higher the speed is, the less time each digit is going to be light on and so, it will dimm naturally.
Have you demonstrated this? Your loop has each digit on for about ¼ the time. Frequency should be irrelevant because with higher frequceny, it will be lit less but will be lit more often. Would not you need to turn the digit off before the pause (or between pauses) to affect the dimness? I will have to think about it more.

PORTA = ~DCD Digit will set 1 bit to a state and all others to the other state; this is an unwanted effect in my case.
I thought you wanted
MAIN:
PORTA = XXXX1110
PORTA = XXXX1101
PORTA = XXXX1011
PORTA = XXXX0111
GOTO MAIN

where the upper nibble were inputs? If they are inputs, they will not be affected by your PORTA=~DCD command because, well, they are inputs.

I didn't think about your solution; it's always amazing to see how many different ways there are to solve a problem. I will try it anyway since I want to know witch is more memory space effective.
Earlier you mentioned speed is an issue, now you mention code space – the unrolled version will not be very code efficient but it should by slightly faster than the looped depending on How PBP converts them to ASM. If one were to write it in ASM, I know the unrolled method would be faster (at least I know I could write an ASM version faster than a looped. Also the PORTA add commands could be done in two instructions versus more as with the >>, & and | approach). However, I still do not know if your upper nibble of PORTA will always be inputs?