Eric Smith wrote:
>
> Wow, you're reading my mind, or more likely my web page.  That's exactly
> how my closed caption decoder works.

No, Eric I haven't read either. However, I'll take a look at your web page.

Andrew Warren wrote:

> Check out my web page for a method with 1.25-cycle resolution... It's
> answer #41, in the "PIC16/17 Answers" section.

Just looked at it. It appears to have single cycle resolution for 8 samples.
After I posted the initial message, I thought of a solution almost identical
to your answer #41 that was good for 15 samples.

First your code segment from answer 41:

        SETUP   MOVLW   00000001B       ;MAKE B0 AN INPUT, B1-B7 OUTPUTS.
                TRIS    PORTB           ;

        SAMPLE  RLF     PORTB           ;SHIFT 7 CONSECUTIVE SAMPLES OF
                RLF     PORTB           ;B0 INTO B7-B1.
                RLF     PORTB           ;
                RLF     PORTB           ;
                RLF     PORTB           ;
                RLF     PORTB           ;
                RLF     PORTB           ;

                MOVF    PORTB,W         ;W-REG CONTAINS LAST 8 SAMPLES
                                        ;(MSB = EARLIEST, LSB = LATEST).
Followed by:
                RLF     PORTB           ;SHIFT NEXT 7 CONSECUTIVE SAMPLES OF
                RLF     PORTB           ;B0 INTO B7-B1.
                RLF     PORTB           ;
                RLF     PORTB           ;
                RLF     PORTB           ;
                RLF     PORTB           ;
                RLF     PORTB           ;

At the end, W contains the first 8 samples and B7-B1 contain the last 7
samples.

You can carry this concept a little bit farther if you wish to sacrifice
ALL I/O ports for this problem. For example, suppose you had a 40 pin
part like the C64, C65, etc. The input signal in addition to being tied to
Port B <0> can also be routed to Port A <0>, Port C <0>, Port D <0>, and
Port E <0>. This would give you an extra 5 + 7 + 7 + 2 = 21 samples for
total of 36 samples.


Any more Ideas?



Scott