Post by thread:[PIC]: ASCII to HEX

On 04-Feb-02 Royce Simmons wrote: > Hi, > > I am looking for a ASCII to HEX conversion assembler routine. I need to > convert 2 ASCII > characters to a single hex digit. All you ever needed to know is at.... http://www.piclist.com/techref/microchip/math/radix/index.htm It only takes 12 instructions..... Maybe you need to find a simpler project to start with ? Read, Understand & Learn from it.... Peter. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body

Royce Simmons <PICLISTKILLspammitvma.mit.edu> wrote: > I am looking for a ASCII to HEX conversion assembler routine. I need > to convert 2 ASCII characters to a single hex digit. Royce: Enter with your two ASCII characters in CHAR1 (tens' digit) and CHAR2 (ones' digit). Exits with CHAR1 and the CHAR2 modified, and the hex value in W. LIST R = DEC MOVLW '0' BTFSC CHAR1,6 MOVLW 'A'-10 SUBWF CHAR1 MOVLW '0' BTFSC CHAR2,6 MOVLW 'A'-10 SUBWF CHAR2 SWAPF CHAR1,W ADDWF CHAR2,W -Andy === Andrew Warren -- .....aiwKILLspam.....cypress.com === Principal Design Engineer === Cypress Semiconductor Corporation === === Opinions expressed above do not === necessarily represent those of === Cypress Semiconductor Corporation -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email EraseMElistservspam_OUTTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

On Mon, 4 Feb 2002 11:18:56 -0800, Andrew Warren wrote: {Quote hidden}>Royce Simmons wrote: > >> I am looking for a ASCII to HEX conversion assembler routine. I need >> to convert 2 ASCII characters to a single hex digit. > >Royce: > >Enter with your two ASCII characters in CHAR1 (tens' digit) and CHAR2 >(ones' digit). Exits with CHAR1 and the CHAR2 modified, and the hex >value in W. > > LIST R = DEC > > MOVLW '0' > BTFSC CHAR1,6 > MOVLW 'A'-10 > SUBWF CHAR1 > > MOVLW '0' > BTFSC CHAR2,6 > MOVLW 'A'-10 > SUBWF CHAR2 > > SWAPF CHAR1,W > ADDWF CHAR2,W > Royce, Andy's code here will work if you need the value expressed in BCD and not its actual hex value. I'm not entirely clear on which one you want. If you need its true hex value, you'll need to multiply the msb digit's numeric value by 10 (decimal) before adding it to the lsb's numeric value. (The SWAPF of CHAR1 actually multiplies it by 16.) In either case, you can remove the BTFSC's and the MOVLW's following them since the BTFSC will always skip the MOVLW. Bit 6 of your digit's ASCII will always be clear for decimal digits '0' through '9'. Regards, Bob -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

Bob Barr <@spam@PICLISTKILLspammitvma.mit.edu> wrote: > Andy's code here will work if you need the value expressed in BCD and > not its actual hex value. > .... > If you need its true hex value, you'll need to multiply the msb > digit's numeric value by 10 (decimal) before adding it to the lsb's > numeric value. Oops, you're right. The correct code: LIST R = DEC MOVLW '0' BTFSC CHAR1,6 MOVLW 'A'-10 SUBWF CHAR1 MOVLW '0' BTFSC CHAR2,6 MOVLW 'A'-10 SUBWF CHAR2 CLRC ;Carry's always set here, so clear it. RLF CHAR1,W ;W = MSB * 2 SWAPF CHAR1 ;CHAR1 = MSB * 16 RRF CHAR1 ;CHAR1 = MSB * 8 ADDWF CHAR1,W ;W = (MSB * 8) + (MSB * 2) = MSB * 10 ADDWF CHAR2,W ;W = MSB * 10 + LSB > In either case, you can remove the BTFSC's and the MOVLW's following > them since the BTFSC will always skip the MOVLW. Bit 6 of your digit's > ASCII will always be clear for decimal digits '0' through '9'. True, but it'll be set for hex digits 'A' through 'F'. If the two input bytes are hex digits in the range 0-F, you need the BTFSC/MOVLWs; if they're only in the range 0-9, you don't. -Andy === Andrew Warren -- KILLspamaiwKILLspamcypress.com === Principal Design Engineer === Cypress Semiconductor Corporation === === Opinions expressed above do not === necessarily represent those of === Cypress Semiconductor Corporation -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body

On Mon, 4 Feb 2002 14:29:55 -0800, Andrew Warren wrote: >Bob Barr wrote: <snip> {Quote hidden}>> >> In either case, you can remove the BTFSC's and the MOVLW's following >> them since the BTFSC will always skip the MOVLW. Bit 6 of your digit's >> ASCII will always be clear for decimal digits '0' through '9'. > > True, but it'll be set for hex digits 'A' through 'F'. > > If the two input bytes are hex digits in the range 0-F, you need >the > BTFSC/MOVLWs; if they're only in the range 0-9, you don't. > Andy, The input digits do have to be in the ASCII '0'-'9' range (otherwise doing the '* 10' wouldn't be right.) Royce's original input data is a pair of decimal characters to be converted to hex. The characters 'A' through 'F' just can't be part of valid input data. Royce, Do you need your result in BCD form (for displaying the two digits) or in its true hex form (for indexing a table or some such)? Regards, Bob -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spamBeGonelistservspamBeGonemitvma.mit.edu with SET PICList DIGEST in the body

Bob Barr <TakeThisOuTPICLISTEraseMEspam_OUTmitvma.mit.edu> wrote: > The input digits do have to be in the ASCII '0'-'9' range (otherwise > doing the '* 10' wouldn't be right.) > > Royce's original input data is a pair of decimal characters to be > converted to hex. The characters 'A' through 'F' just can't be part of > valid input data. See? THIS is what happens when you take a perfectly good software guy and make him work on everything BUT software for a year and a half. Sigh... Ok, my code and I were both confused. Here's the routine to translate two ASCII hex digits (0-9 or A-F) into a hex value. I don't remember Royce saying that his two ASCII digits were decimal, so this might be what he wanted: LIST R = DEC MOVLW '0' BTFSC CHAR1,6 MOVLW 'A'-10 SUBWF CHAR1 MOVLW '0' BTFSC CHAR2,6 MOVLW 'A'-10 SUBWF CHAR2 SWAPF CHAR1,W ADDWF CHAR2,W (By the way... On piclist.com, there's a code fragment attributed to me which purports to perform the above translation. It contains two extra lines between the SWAPF and the final ADDWF; I have no idea how those lines got there, and can only assume that the code was taken out of context.) Here's the code to translate two ASCII decimal digits (0-9) into a hex value. If Royce's input characters ARE decimal, this is the routine he wants: LIST R = DEC MOVLW '0' SUBWF CHAR1 SUBWF CHAR2 CLRC ;Carry's always set here, so clear it. RLF CHAR1,W ;W = MSB * 2 SWAPF CHAR1 ;CHAR1 = MSB * 16 RRF CHAR1 ;CHAR1 = MSB * 8 ADDWF CHAR1,W ;W = (MSB * 8) + (MSB * 2) = MSB * 10 ADDWF CHAR2,W ;W = MSB * 10 + LSB -Andy === Andrew Warren -- RemoveMEaiwTakeThisOuTcypress.com === Principal Design Engineer === Cypress Semiconductor Corporation -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservEraseME.....mitvma.mit.edu with SET PICList DIGEST in the body

Thanks All, I really appreciate all the answers. The code below is what I was looking for. I had worked on this this morning and I had almost the code below but I did not use the neat trick of setting up a default subtraction value before testing the input character. I am learning slowly but well, I think. I had 2 hex characters (0 to F) for input and I needed the get the result in the W reg as a hex number, ex: IN = A1 (ASCII), output = A1 (HEX). Works great, Royce {Original Message removed}

On Mon, 4 Feb 2002 20:32:53 -0500, Royce Simmons <EraseMEw2rbnPRODIGY.NET> wrote: >Thanks All, > >I really appreciate all the answers. The code below is what I was looking >for. I had worked >on this this morning and I had almost the code below but I did not use the >neat trick of setting >up a default subtraction value before testing the input character. I am >learning slowly but >well, I think. I had 2 hex characters (0 to F) for input and I needed the >get the result in the W reg >as a hex number, ex: IN = A1 (ASCII), output = A1 (HEX). > Sorry, my mistake. I thought you had two decimal digits as your input. Regards, Bob -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email RemoveMElistservEraseMEEraseMEmitvma.mit.edu with SET PICList DIGEST in the body