Assembly Implementation

As discussed earler, we can implement I2C by bit-banging on 8051 using any two pins. Here in implementation below we have used P0.0 for SDA (serial data) and P0.1 for SCL (serial clock).

;***************************************
;Ports Used for I2C Communication
;***************************************
	sda equ P0.0
	scl equ P0.1

;***************************************
;Initializing I2C Bus Communication
;***************************************
i2cinit:
	setb sda
	setb scl
	ret

;****************************************
;ReStart Condition for I2C Communication
;****************************************
rstart:
	clr scl
	setb sda
	setb scl
	clr sda
	ret

;****************************************
;Start Condition for I2C Communication
;****************************************
startc:
	setb scl
	clr sda
	clr scl
	ret

;*****************************************
;Stop Condition For I2C Bus
;*****************************************
stop:
	clr scl
	clr sda
	setb scl
	setb sda
	ret

;*****************************************
;Sending Data to slave on I2C bus
;*****************************************
send:
	mov r7,#08
back:
	clr scl
	rlc a
	mov sda,c
	setb scl
	djnz r7,back
	clr scl
	setb sda
	ret

;*****************************************
;ACK and NAK for I2C Bus
;*****************************************
ack:
	clr sda
	setb scl
	clr scl
	setb sda
	ret

nak:
	setb sda
	setb scl
	clr scl
	setb scl
	ret

;*****************************************
;Receiving Data from slave on I2C bus
;*****************************************
recv:
	mov r7,#08
back2:
	clr scl
	setb scl
	mov c,sda
	rlc a
	djnz r7,back2
	clr scl
	setb sda
	ret
		

C Implementation

#define SDA P0_0
#define SCL P0_1

void I2CInit(){
	SDA = 1;
	SCL = 1;
}

void I2CStart(){
	SCL = 1;
	SDA = 0;
	SCL = 0;
}

void I2CRestart(){
	SDA = 1;
	SCL = 1;
	SDA = 0;
}

void I2CStop(){
	SDA = 0;
	SCL = 1;
	SDA = 1;
}

void I2CAck(){
	SDA = 0;
	SCL = 1;
	SCL = 0;
}

void I2CNak(){
	SDA = 1;
	SCL = 1;
	SCL = 0;
}

unsigned char I2CSend(unsigned char Data){
	 unsigned char i, ack_bit;
	 for(i=0;i<8;i++){
	 	SCL = 0;
		if ((Data & 0x80) == 0)
			SDA = 0;
		else
			SDA = 1;
		SCL = 1;
		Data<<=1;
	 }
	 SCL = 0;
	 ack_bit = SDA;
	 SCL = 1;
	 SCL = 0;
	 return !ack_bit;
}

unsigned char I2CRead(){
	unsigned char i, Data=0;
	for(i=0;i<8;i++){
		SCL = 0;
		SCL = 1;
		if(SDA)
			Data |=1;
		if(i<7)
			Data<<=1;
	}
	SCL = 0;
	SDA = 1;
	return Data;
}
		

Using the above implementation is really easy, next part uses an example of interfacing DS1307 with AT89C51 to read RTC registers (0x00 to 0x07).

Forum Activity
majoka Avatar
Posted By majoka
Wed Jul 30 2014, 02:45 PM
@ sermeteraythank you for sharing your experience ...
majoka Avatar
Posted By majoka
Wed Jul 30 2014, 02:38 PM
@ Peter_ParkerHC06 by default baud rate is 9600try...
majoka Avatar
Posted By majoka
Wed Jul 30 2014, 02:25 PM
attach is the code for lcd may be need a little ch...
majoka Avatar
Posted By majoka
Wed Jul 30 2014, 02:21 PM
@ pravin_35both compilers are almost sameif you ha...
pravin_35 Avatar
Posted By pravin_35
Wed Jul 30 2014, 07:38 AM
http://extremeelectronics.co.in/pic16f877a-tutoria...
NexusRevZ Avatar
Posted By NexusRevZ
Wed Jul 30 2014, 02:31 AM
Ok, I have edited the code, it's updated above wit...
NexusRevZ Avatar
Posted By NexusRevZ
Wed Jul 30 2014, 02:10 AM
Oh tahnk you so much for the reply. I will do imme...
ajay_bhargav Avatar
Posted By ajay_bhargav
Wed Jul 30 2014, 01:56 AM
You cannot move and read data from EEPROM immediat...
pravin_35 Avatar
Posted By pravin_35
Wed Jul 30 2014, 12:39 AM
Remove all power connections to the circuit at the...
NexusRevZ Avatar
Posted By NexusRevZ
Tue Jul 29 2014, 09:31 PM
This simple code is test the write and read of EEP...

Conversation

NexusRevZ
Tue Jul 29 2014, 09:32 PM
Anyone good in Asm lang?
ajay_bhargav
Mon Jul 28 2014, 12:34 AM
@ Anshu Raj sorry we do not take such requests.
Sun Jul 27 2014, 12:23 AM
Anshu Raj
sir plz send the automatic collage alram bells in 2 hrs bells ring. For microcontroller programme plz sir
ajay_bhargav
Thu Jul 24 2014, 01:06 AM
@R.ABHISHEK where? I dont see it. is it in forum?
Wed Jul 23 2014, 05:49 AM
R.ABHISHEK
sir,pls message on microcontroller 8051 assambly language new program
Wed Jul 23 2014, 05:47 AM
R.ABHISHEK
sir,pls message on 8051 microcontroller assambly language program new quastions
ajay_bhargav
Tue Jul 22 2014, 09:18 AM
@Pragya Android application is taken from google play. Only Author has its source with him. Application is only used in this project.
Tue Jul 22 2014, 04:58 AM
Pragya
plz send me 8051 code and android code for android based device controller via Bluetooth .Here in this project I am using Hc-06 Bluetooth module
Thu Jul 10 2014, 09:57 AM
Caleb
plz someone mail me the source code for that project
Thu Jul 10 2014, 09:57 AM
Caleb
http://www.8051projects.net/download-d188-control-your-pc-tv-remote.html

Downloads

Comments

NexusRevZ
Tue Jul 29 2014, 09:29 PM
kritz22
Mon Jul 28 2014, 10:33 AM
Abbasans786
Mon Jul 28 2014, 03:15 AM
Imran.pk
Fri Jul 25 2014, 07:50 PM
PavanKh
Fri Jul 25 2014, 12:56 AM
vinosentinal
Mon Jul 21 2014, 08:28 PM
niks_here
Sun Jul 20 2014, 05:38 PM
athiramsankar
Sun Jul 20 2014, 12:00 PM

Online

Guests: 46, Members: 0 ...

most ever online: 182184
(Members: , Guests: 182184) on 06 Aug 2010: 01:37 AM

Members: 37484
Newest member: NexusRevZ