Hey guys,

As you've gathered from my "parts sourcing" post, I am in the heat of the battle on my "code sniffer" project. I thought I had the code to check for valid digits licked but then...doh!
Code:
        EEAddress=414
        I2CREAD I2cData,I2cClock,$A0,EEAddress,[CheckPanelDigit]
        IF CheckPanelDigit < 153 THEN
            EEAddress=415
                I2CREAD DPIN,CPIN,$A0,EEAddress,[CheckPanelDigit]
                    IF CheckPanelDigit < 153 THEN      'BETWEEN HEX 00 AND 99
                        Goto ConcordExpress
                    else
                        goto SnifferErr
                    endif
        else
            goto SnifferErr
        endif
As I am checking for "valid" digits, I figured I could just make sure they are below DEC 153 (Hex 99). Well, what if I happen to get a "8E" (DEC 142)? The code will execute, which I can't allow to happen. I guess the easiest way to explain it is: the hex received must have 2 valid digits in it, 0-9.
Is there a routine, or a bit of math trickery I can perform to do the verification of the hex pair?
Whew, I think I confused myself after reading this post!
I hope it makes sense to one of you.

Thanks guys,
Chris