Hello Every body,

The situation is little bit confusing, (Because i am now stucked on IIC), well i am working with AT89C2051 and AT24C04 and as i am new to IIC so i am stucked badly, :-(

Well i have readed Essential Reading about the IIC and the AT24C04, and i have codded a program, and the program is working just fine in Simulator, well i am using Keil-C51-V3 (eval ver), and i have anyalised that the waveforms of the SCK and SDA are just fine, but i dont know that why the MCu is not writing the Data to EEPROM,

Well i Playing with Port-1 to ensure that data writtend successfully, :-) so i think that no need to worry,

So any help will be Appritiatable, (Although i have nice experiance of posting in 8052 :-) )

Well here is the Link of the Image of the Wave form Caught from KEIL,


(The Red Mark In wave Shows the Condition when Data Written Successfully)

Well the problem is that i the Port-1 (P1) is not becomming 00h, and Held to FFh which is default, and according to me if the Data Writing is in success then P1 should become 00h, i think it is very straight forward

			ORG 0000H
			LJMP MAIN
			ORG 0030H
			SCK EQU P3.5
			SDA EQU P3.4
			TST EQU P3.7
			DYTA EQU 30H
			ADDRE EQU 31H

MAIN:		SETB TST			;Setting TST button
			MOV P1,#0FFH		;Setting all bits of P1 to high
			CLR A			;Clearing the variables
			MOV R7,A		;Clearing the Counter R7
			MOV ADDRE,A		;Moving Address 00h to ADDRE
			MOV DYTA,A		;Moving Data Location 30h to 00h		
			MOV ADDRE,#00000000B	;Want to write the Byte to 00h of EEPROM
			MOV DYTA,#11110000B	;Wand to write F0h to 00h Location of EEPROM 
			LCALL WRITE		;Calling the Write Routine
			MOV P1,#000H		;Clearing the P1 to confirm data written Succesfully
AGAIN:		JB TST,$			;Wait until the TST button to Ground
			JNB TST,$		;Wait untill button released
			MOV ADDRE,#00000000B	;Setting the Address 00h for reading
			LCALL READ		;Calling the Read Routine
			MOV A,DYTA		;Copy the DYTA to ACC
			MOV P1,A		;Mov the ACC to P1
			SJMP AGAIN		;Do it again

;===============================================
;==============SUBROUTINES======================
;===============================================

WRITE:		LCALL IIC_START			;IIC Start Routine
			MOV A,#10100000B	;Moving the Address of Slave to Acc with Write
			LCALL CLOCK_D		;Clock the Acc to SDA and SCK
			LCALL ACK		;Wait for Acknowledge
			MOV A,ADDRE		;Mov the Address
			LCALL CLOCK_D		;Clock the Address of EEPROM
			LCALL ACK		;Wait for Acknowledge
			MOV A,DYTA		;Mov the Data
			LCALL CLOCK_D		;Clock the Data
			LCALL ACK		;Wait for Acknowledge
			LCALL IIC_STOP		;IIC Stop Routine
			LCALL DELAY		;Simple Delay Routine
			RET

READ:		LCALL IIC_START			;IIC Start Routine
			MOV A,#10100000B	;Moving the Address of Slave to Acc with Write
			LCALL CLOCK_D		;Clock the Acc to SDA and SCK
			LCALL ACK		;Wait for Acknowledge
			MOV A,ADDRE		;Mov the Address
			LCALL CLOCK_D		;Clock the Address of EEPROM	
			LCALL ACK		;Wait for Acknowledge
			LCALL IIC_START		;Again IIC Start Routine
			MOV A,#10100001B	;Moving the Address of Slave to Acc with Read
			LCALL CLOCK_D		;Clock the Acc to SDA and SCK
			LCALL ACK		;Wait for Acknowledge
			LCALL I2C_READ		;Read the Data with SDA and SCK
			LCALL NO_ACK		;No Acknowledge Condition
			LCALL IIC_STOP		;IIC Stop Routine
			RET

NO_ACK:    	SETB SDA
			CLR SCK
			JNB SDA,$		
			SETB SCK
			RET


ACK:   		SETB SDA
			SETB SCK
			JB SDA,$		;Wait for Acknowledge
			CLR SCK
			RET

I2C_READ: 	MOV R7,#8
GFD:		SETB SDA
			SETB SCK 
			MOV C,SDA 
			RLC A
			CLR SCK
			DJNZ R7,GFD
			MOV DYTA,A
			RET

			RET
CLOCK_D:	RLC A
			MOV R7,#8

LOOP:		MOV SDA,C
			SETB SCK
			CLR SCK
			RLC A
			DJNZ R7,LOOP
			RET

DELAY:		MOV R7,#8
			DJNZ R7,$
			RET

IIC_STOP:	CLR SDA
			SETB SCK
			SETB SCK
			SETB SDA
			RET

IIC_START:	SETB SCK
			SETB SDA
			CLR SDA
			CLR SCK
			RET
			
DELAY_STOP:	MOV TMOD,#00000001B
			MOV TH0,#0EEH 
			MOV TL0,#00H
			SETB TR0
SAC:		JNB TF0,SAC
			CLR TR0
			CLR TF0
			RET

			END