I2C with External Eeprom

[ruijc]

WP is connected to ground. Same as all address pins of the eeprom.

[skimask]

WP is connected to ground. Same as all address pins of the eeprom.

Then I'd suggest backing up a bit...
Get uncomplicated...
Write some code to just write a few values to the eeprom and read them back to verify what was written...THEN write the code you actually want to use...'cause I see a few flaws in your logic in the code written a few posts back.

[ruijc]

Thanks skimask,

Good idea. Will do that tonight and post the results

.

[ruijc]

Just finished assembling a small code and still cannot work with the eeprom

this is the code i used :

'****************************************************************

'****************************************************************


SSPCON.5 = 0                ; Disable SSP Module
TXSTA.5 = 0                 ; Disable AUSART Tx
RCSTA.7 = 0                 ; Disable Serial Port
 

OSCCON = %01111110 'Internal RC w/ I/Os

INTCON=0

PIE1     = 0
'PIE2    = 0

PIR1 = 0   	'off

CMCON= 7   	'COMPARATOR OFF          
CVRCON= 0 	'Vref Off
CCP1CON= 0

T1CON= 0
'T2CON = %00000100

osctune=0

'*****************************************************************************
'DEFINEs
'*****************************************************************************

@ DEVICE INTRC_OSC
@ DEVICE MCLR_OFF
@ DEVICE PROTECT_OFF

DEFINE osc 8

@ DEVICE CPD_OFF
@ DEVICE LVP_OFF
@ DEVICE BOD_OFF
@ DEVICE PWRT_OFF
@ DEVICE WDT_OFF
 
'*****************************************************************************
 

'*****************************************************************************
'ADC parameters

ADCON1  =%10000000      'right justify
ANSEL   =%00000001 	'PORTA.0 ANALOG
ADCON0  =%11000001     

'*****************************************************************************
 
INCLUDE "modedefs.bas" 

'settings for serial comm

DEFINE debug_reg PORTB  
DEFINE debug_bit 7
DEFINE debug_baud 9600
DEFINE debug_mode 1

'*****************************************************************************
'I/O's
 
PORTA=0
PORTB=0

TRISA=%00000001		'PORTA.0 AS INPUT
TRISB=%00000111		'SDA,SCL AND BUT1 AS INPUTS
 
'*****************************************************************************
'PINS
 
A0    	var PORTA.0 
a1     	var PORTA.1 
A2    	var PORTA.2 
A3      var PORTA.3 
A4      var PORTA.4 
MCLR    var PORTA.5 
a6    	var PORTA.6 
a7    	var PORTA.7 

SDA    	var 	PORTB.0   'I2C DATA PIN
SCL    	var 	PORTB.1   'I2C CLOCK PIN
but1    var 	PORTB.2   'BUTTON FOR LOOP
b3     	var 	PORTB.3

B4    	var PORTB.4  
B5    	var PORTB.5  
B6    	var PORTB.6  
out    	var PORTB.7

'*****************************************************************************
' variables


mem      var 	byte

ADDR    var 	word
m1      var 	word
m2      var 	word
CTW	VAR	WORD

'*****************************************************************************

CTW=$A0
m1=0
m2=0

'*****************************************************************************

start:

I2CREAD SDA,SCL,CTW,$1,[m1]
pause 10

debug " value IN EEPROM address 1 =  ",dec m1,13,10

I2CREAD SDA,SCL,CTW,$10,[m2]
pause 10

debug " value IN EEPROM address 10 =  ",dec m2,13,10

I2CWRITE SDA,SCL,CTW,$1,[5]
PAUSE 10

debug " WROTE 5 at address 1 =  ",13,10

I2CWRITE SDA,SCL,CTW,$10,[6]
PAUSE 10

debug " WROTE 6 at address 10 =  ",13,10


loop:
if but1=1 then 
goto start
else 
goto loop
endif

end

The value returned for both addresses is 257

Just as a note, with the first code ( showned in post #4 ) the returned value was always 8 ( for any address ) and 0 when removing the pullups.

EDIT:
Changed the lines:

I2CWRITE SDA,SCL,CTW,$1,[5]

to

ADDR=$1
I2CWRITE SDA,SCL,CTW,ADDR,[5]

( as seen in Melanie's post about I2C )
http://www.picbasic.co.uk/forum/showthread.php?t=587

but the return value is the same

[skimask]

DEFINE OSC 8
INCLUDE "modedefs.bas" 
@ DEVICE INTRC_OSC
@ DEVICE MCLR_OFF
@ DEVICE PROTECT_OFF
@ DEVICE CPD_OFF
@ DEVICE LVP_OFF
@ DEVICE BOD_OFF
@ DEVICE PWRT_OFF
@ DEVICE WDT_OFF
DEFINE DEBUG_REG PORTB  
DEFINE DEBUG_BIT 7
DEFINE DEBUG_BAUD 9600
DEFINE DEBUG_MODE 1
osccon=$7e:cmcon=7:adcon1=$80:ansel=1:adcon0=$c1:porta=0:portb=0:trisa=1
trisb=7:sda var portb.0:scl var portb.1:addr var word:dat var byte
dat2 var byte:ctw con $a0
start:     dat=dat+1:addr=addr+1
i2cwrite sda,scl,ctw,addr.highbyte,addr.lowbyte,[dat]:pause 10
debug "Wrote: ",dec addr," with ",dec dat,13,10
i2cread sda,scl,ctw,addr.highbyte,addr.lowbyte,[dat2]
debug " Read: ",dec addr," val: ",dec dat2 , 13 , 10
if dat = dat2 then
debug "Write/Read Successful at ",dec5 addr," with ",dec3 dat,13,10
else
debug "Write/Read Error at ",dec5 addr,"-Wrote:",dec3 dat," - Read:",dec dat2,13,10
endif
pause 500:goto start
END

OR un-COLONized...

DEFINE OSC 8
INCLUDE "modedefs.bas" 
@ DEVICE INTRC_OSC
@ DEVICE MCLR_OFF
@ DEVICE PROTECT_OFF
@ DEVICE CPD_OFF
@ DEVICE LVP_OFF
@ DEVICE BOD_OFF
@ DEVICE PWRT_OFF
@ DEVICE WDT_OFF
DEFINE DEBUG_REG PORTB  
DEFINE DEBUG_BIT 7
DEFINE DEBUG_BAUD 9600
DEFINE DEBUG_MODE 1
osccon = $7e
cmcon = 7
adcon1 = $80
ansel = 1
adcon0 = $c1
porta = 0
portb = 0
trisa = 1
trisb = 7
sda var portb.0
scl var portb.1
addr var word
dat var byte
dat2 var byte
ctw con $a0

start:
dat = dat + 1
addr = addr + 1
i2cwrite sda , scl , ctw , addr.highbyte , addr.lowbyte , [ dat ]
pause 10
debug "Wrote: " , dec5 addr , " with " , dec3 dat , 13 , 10
i2cread sda , scl , ctw , addr.highbyte , addr.lowbyte , [ dat2 ]
debug " Read: " , dec5 addr , " val: " , dec3 dat2 , 13 , 10
if dat = dat2 then
debug "Write/Read Successful at " , dec5 addr , " with " , dec3 dat , 13 , 10
else
debug "Write/Read Error at " , dec5 addr , "-Wrote:" , dec3 dat , " - Read:" , dec dat2 , 13 , 10
endif
pause 500
goto start
END

[ruijc]

Hi skimask,

i'm pleased to say that your code worked. Thank you very much for your help

Will re-write my entire code from scratch.

I have some notes here and i will see what happens.

.

[skimask]

Hi skimask,
i'm pleased to say that your code worked. Thank you very much for your help
Will re-write my entire code from scratch.
I have some notes here and i will see what happens.
.

Really?
That's amazing...because I did a quick search a couple days ago for 24LC512 here on THESE forums and, except for COLON-izing the one listing, practically did a cut-and-paste.
Search engine must've been broken that day...huh?