Byron, thank you for your reply.  You have given me several things to
think about.  After seeing your code snippet, I have decided I should
really try to work out this whole problem myself instead of hacking up a
complete piece of code I found from Microchip.  I have started to sketch
out the problem in pseudo code.

> Here's a brain plant for you to think about later on. While assembly
is
> essential to learn, both for reading other's programs and for high
> performance computing, Having abstraction for simple projects can
really
> help.

Abstraction is something I have considered.  When I write my own code, I
usually sketch everything out in pseudo code that resembles C.  Then I
write the Assembly code a chunk at a time.  A step beyond this would be
to actually use a higher level language.  For this project, I would like
to stick to Assembly because that's the first language I have any
experience with on the PIC and it is helping me understand how the chip
actually works.  But, I will look into the languages you list on your
web page at http://www.finitesite.com/d3jsys/languages.html.  Up until
now, JAL is the only one of the three I have heard of.

>         CBLOCK   0x2C   ; CBLOCK will auto the address.
>                         ; 0x2C works for most 16F style pics.
>         display         ; Make sure to init to 0
>         ENDC

> Update  incf     display,W  ; Next display
>         andlw    0x03       ; Keep in range
>         movwf    display    ; And stick it back in display
>         clrf     PCLATH     ; Paranoia. Keep in 1st page
>         call     disp2bit   ; Convert to a bit number
>         movwf    PORTA      ; and write to port A.
>         return              ; C-YA!

> ; disp2bit presumes a couple of things. One is that W has the display
> number.
> ; Two is that PCLATH is cleared. Fix as necessary.

> disp2bit
>        andlw     0x03       ; Paranoia. Just in case W > 3
>        addwf     PCL,F      ; Jump table add
>        retlw     0x0E       ; Clear PORTA:0
>        retlw     0x0D       ; Clear PORTA:1
>        retlw     0x0B       ; Clear PORTA:2
>        retlw     0x07       ; Clear PORTA:3

Has someone on this PICList posted standards for coding and commenting?
I mean, how many tabs to indent for code and comments, what to
capitalize, etc.

> You have another issue to think about. It's very likely that if you
are
> using a port pin to drive the cathode, that the display will be too
dim to
> be useful.

You're definitely right about this.  I prefer using a transistor for
each display.  It helps me to keep all the work in the PIC instead of
depending on logic in another chip, but either method would work.  Have
far along are you on segment multiplexing?  That would solve the power
problem for my situation, but I expect it would require quite a bit more
code.

Thanks!
-Pat

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