I2C Slave with a PIC

[Darrel Taylor]

In your previous code with the F88, 3 is not a valid I2C address.
In the current code, $B is not a valid I2C address.

They should be a multiple of 2.
Bit 0 is reserved for the R/W bit.

[tacbanon]

In your previous code with the F88, 3 is not a valid I2C address.
In the current code, $B is not a valid I2C address.

They should be a multiple of 2.
Bit 0 is reserved for the R/W bit.

Hi Darrel,
Thanks for replying, I did some testing on 1Master and 1Slave with these address($02,$04,$06,$08,$10,$12,$14) and works fine. But when I trying to add Slave #2 I get "0 0 0 0 0 0". It only reads on the Slave #1 correct (displays "1 2 3 4 5 6").
This is how I code to read the 2nd Slave.

DEFINE OSC 40


DEFINE I2C_HOLD 1


DEFINE LCD_DREG         PORTB          
DEFINE LCD_DBIT         0              
DEFINE LCD_RSREG        PORTB         
DEFINE LCD_RSBIT        4             
DEFINE LCD_EREG         PORTB          
DEFINE LCD_EBIT         5             
DEFINE LCD_BITS         4           
DEFINE LCD_LINES        2              
DEFINE LCD_COMMANDUS    2000         
DEFINE LCD_DATAUS       50           
PAUSE 100
LCDOUT $FE,1,$FE,2


ADCON1=001111
CMCON=000111


scl             VAR PORTC.3
sda             VAR PORTC.4                    


i2c_address     VAR BYTE
i2c_address2     VAR BYTE


i2c_data        VAR BYTE[6]
i2c_data2       VAR BYTE[6] 




main:


i2c_address=$10
pause 200
I2CREAD sda,scl,i2c_address,[STR i2c_data\6]
LCDOUT $FE,$80,"1> ",DEC i2c_data[0]
LCDOUT " ",    DEC i2c_data[1]
LCDOUT " ",    DEC i2c_data[2]
LCDOUT " ",    DEC i2c_data[3]
LCDOUT " ",    DEC i2c_data[4]
LCDOUT " ",    DEC i2c_data[5]


PAUSE 500
LCDOUT $FE,1
'*********************************************
i2c_address2=$14
pause 200
I2CREAD sda,scl,i2c_address2,[STR i2c_data2\6]
LCDOUT $FE,$80,"2> ",DEC i2c_data2[0]
LCDOUT " ",    DEC i2c_data2[1]
LCDOUT " ",    DEC i2c_data2[2]
LCDOUT " ",    DEC i2c_data2[3]
LCDOUT " ",    DEC i2c_data2[4]
LCDOUT " ",    DEC i2c_data2[5]


PAUSE 500
LCDOUT $FE,1  
GOTO main

BTW the code for Slave1 and Slave2 are identical (Slave#1 is address $10 and Slave#2 is address $14)
What I'm doing wrong in the code? I appreciate very much your help.

Thanks,
Tacbanon

[Darrel Taylor]

If you comment out the first I2CREAD, is it able to read from the second slave?

If you change the order so that it reads the second slave first, is it then unable to read the first slave?

[tacbanon]

If you comment out the first I2CREAD, is it able to read from the second slave?

Yes it is able to read.

If you change the order so that it reads the second slave first, is it then unable to read the first slave?

Nope, displays "0 0 0 0 0 0" for first Slave, 2nd Slave shows "6 5 4 3 2 1"

[Darrel Taylor]

It sounds like a buffer overflow.

... bad comment deleted ... duh!!

If you post or email your .DSN, I'll take a closer look.

[tacbanon]

Thanks Darrel, oh sorry to ask this, but how do I send a winrar file?

[mister_e]

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