I have a problem to wake PIC 16F877 up by signal on RB0 in the right time.
The datasheet told me it was about 250 uS (4MHz clock, PWRTE not set). It's
about 4 mS by my measurement. What do I miss?

Igor



-----Original Message-----
From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On
Behalf Of Hazelwood Lyle
Sent: Monday, June 09, 2003 7:35 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] char to int


>-----Original Message-----
>From: Chris Loiacono [mailto:chris@MAIL2ASI.COM]
>Sent: Monday, June 09, 2003 12:39 PM
>To: PICLIST@MITVMA.MIT.EDU
>Subject: char to int
>
>
>Earlier this month there was a brief discussion on converting integers to
>characters.
>
>Is there a simple gem for converting characters to integers?
>

Just off the top of my head, (WARNING, UNTESTED PSEUDO_CODE FOLLOWS)
Not optimized, just fairly easy to read. Could use less space and
registers. Written for 18F instruction set.

Will read an arbitrary number of digits until a non-numeric digit
is read. That digit is "lost".

Reads from "getnext"

For 0-255, with or without leading zeros, decimal to binary
whole numbers only. A decimal point will terminate input.

ten             RES     01
result  RES     01
scratch RES     01

ASC2BIN
        movlw   .10
        movwf   ten
        clrf    result
loop
        call getnext    ;get next digit into W

                        ;convert from ASCII to value
        sublw   '0'             ;subtract ASCII Zero

                        ;test for non-numeric data
        bn      outtahere       ;character less than '0', we are done
        cpfslt ten              ;skip if result less than 10
        bra     outtahere       ;character greater than '9', we are done

                        ;calculate new result
        movwf   scratch ;intermediate storage of new digit
        movf    result,w        ;get current result into W
        mullw   .10             ;multiply current result by ten (into PRODL)
        movf    PRODL,w
        addwf   scratch ;add newest digit
        movwf   result
        bra     loop            ;go get next character

outtahere                       ;conversion complete
        movf    result,w
        return


I hope I got it right.
If not as working code then at least an example of method.
I am quite sure there are many here with shorter/faster/more
efficient/better featured ways.
Should be fairly easy to rewrite for 16 bit results.

Good Luck,
(Hoping to avoid flames for less than perfect code)
Lyle

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