.include "m16def.inc"

.CSEG
rjmp start

.ORG $13
start:
ldi r16,LOW(RAMEND)		;Stack anlegen
out SPL,r16
ldi r16,HIGH(RAMEND)
out SPH,r16

ldi r16,0xFF
out DDRA,r16
out DDRB,r16

ldi r19,10
out TWBR,r19
ldi r19,$1
out TWSR,r19

ldi r21,0
ldi r22,0x1c
ldi r23,0b11111111
rcall write
ldi r21,0
ldi r22,0x1c
rcall read

in r19,TWDR
out PORTB,r19

loop:			
rjmp loop

write:
ldi r18,(1<<TWINT)|(1<<TWSTA)|(1<<TWEN) ;starten
out TWCR,r18
rcall warten

ldi r19,0b10100000						;Adresse senden
out TWDR,r19
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten

out TWDR,r21							;1byte senden				
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten

out TWDR,r22							;2byte senden
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten

out TWDR,r23							;3byte senden
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten

ldi r18,(1<<TWINT)|(1<<TWSTO)|(1<<TWEN)	;stoppen
out TWCR,r18
reti

read:
ldi r18,(1<<TWINT)|(1<<TWSTA)|(1<<TWEN) ;starten
out TWCR,r18
rcall warten

ldi r19,0b10100000						;adresse senden
out TWDR,r19
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten

out TWDR,r21							;1byte senden				
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten

out TWDR,r22							;2byte senden
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten


ldi r18,(1<<TWINT)|(1<<TWSTA)|(1<<TWEN) ;starten
out TWCR,r18
rcall warten

ldi r19,0b10100001
out TWDR,r19
ldi r18,(1<<TWINT)|(1<<TWEN)
out TWCR,r18
rcall warten

nop

ldi r18,(1<<TWINT)|(1<<TWSTO)|(1<<TWEN) ;stoppen
out TWCR,r18
reti

warten:
push r18
warten1:
in r18,TWCR
sbrs r18,TWINT
rjmp warten1
pop r18
reti

.EXIT