AVR-Chat

Hi All

Just to rap this up, were did I go wrong? is all the help from Richard described in a text book or a AVR
tutorial on the AVR Studio?

The help I got from Richard uses ".DB" I notice it is listed in "Assembler directives" along with
.CSEG
.DEF
.ENDMICRO
.ESEG
.EQU
.INCLUDE
.MACRO
.ORG

in chapter "Annex" pages 41 to 52 from Avr-tutorial from the web site of www.avr-asm-tutorial.net


I must go and buy that book someone recommended (when I get enough money together)


From Eric




----- Original Message -----
From: "Eric" <erichards@clear.net.nz>
To: <AVR-Chat@yahoogroups.com>
Sent: Wednesday, February 16, 2005 7:06 AM
Subject: Re: [AVR-Chat] writing a message for a multi character LCD



Thank you Richard
The program works great only had to change "wrt_db" to "putc" .

I  thought there must be some "tidy" way of doing it,

From Eric





----- Original Message -----
From: "Richard Reeves" <r_reeves@blueyonder.co.uk>
To: <AVR-Chat@yahoogroups.com>
Sent: Wednesday, February 16, 2005 4:20 AM
Subject: Re: [AVR-Chat] writing a message for a multi character LCD



> How can you write a assembly function to put messages on a LCD without
> doing multiple
>
>
>    ldi    r16,0x61           ; 'a' to lcd
>    call   putc                 ; send character to LCD
>    ldi    r16,0x62           ; 'b' to lcd
>    call   putc                 ; send character to LCD
>    ldi    r16,0x63           ; 'c' to LCD
>    call   putc                 ; send character to LCD
The way I do it is to write the string like this at the end of the code:

message: .db "This is a message",$ff

Then do this:
mess:ldi zl,low(message*2) ;load base address of string
     ldi zh,high(message*2);load base address of string
loop:lpm r16,z+            ;Load character from address in z to r16, inc z
     cpi r16,$ff           ;Check for string terminator character
     breq exit             ;If equal quit
     rcall c           ;If not equal, display character and loop
     rjmp loop
exit:ret


Richard
--
Na vratima raja, ja savijam krila...
http://www.van-gogh.co.yu




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