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Message

EEPROM

2009-03-11 by Guido Helmstetter

Hi
This is my first message.
I am going through the tutorial from microcontroler.net. It is very good until the thing with the eeprom. I am not downloading to the tiny45 yet. just observing in studio4.16.
When setting read of eeprom  with sbi eecr, eere. eedr displays instantly all so good but not the entry on the eseg table but just xff.  looked far and wide there was one entry, of a fix  but in c well that is i am using assembler. Nothing on atmel either but i started getting suspicious about 4.16 reading a post in freaks, where there are problems with the latest version of studio. Nonetheless I figure the problem is more likely me. Here is the code.
 
Thanks in advance well I know this is not going to tickle anyones brain much. But it is a beginning into AVR.
guido
 
;**************************
.def temp = r16
.def temp1 = r17
.def count = r18
.def count1 = r19
;
.nolist
.include "C:\Program Files\Atmel\AVR Tools\AvrAssembler\Appnotes\tn45def.inc"
.CSEG
.ORG 0000
  rjmp start
;***************;delay
delay:
 ldi count, 0x00
wait:
 ldi count1, 0x00
wait1: 
dec count1
 brne wait1
 dec count
 brne wait
 ret
;****************;delay
start:
 ldi temp, low(RAMEND)  ;Stackpointer initialisieren
 out SPL, temp
 ldi temp, high(RAMEND)
 OUT SPH, temp
   
 ldi     ZL, low(cnt)       
     ldi     ZH, high(cnt)
  rcall   EEPROM_read          ;read data eeprom
    
loop:
 rjmp loop 
EEPROM_read:
    sbic    EECR,EEPE            ;check for write over
    rjmp EEPROM_read       
 clr temp
 out sreg, temp                    ;clear sreg
 out EEARL, temp1                    ;temp1 inc in table
 sbi EECR, EERE                     ;set read bit
     in temp1, EEDR                  ;return data from table eseg
                    
 out     PORTB, temp1
 rcall delay
 inc temp1
 cpi temp1, 2                      ;inc pointer and check with constant
 brne EEPROM_read
    ret 
 
.eseg                               ;Daten im EEPROM definieren
cnt:
 .db     0b10101010
 .db 0b01010101


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