i2c communication problem with pic18f2520

[nehallove]

hi guys,

i am tryin to communicate with the ad5933 chip with i2c communication protocol ... the communication code is also given below. the thing i m missing is that if i do single step then i get to read the rite value but if run the code free then it won't run properly.

code:

int8 AD5933readbyte(unsigned char address)
{
int1 ack_rcv; // Receives acknowledge bit from transaction. CCS defined type.
int8 byte_rcv; // Receives the byte transmitted by the AD5933.

/* Initialize the address to be read back from by setting a pointer. */
i2c_start(); // Starts I2C transaction.
ack_rcv = i2c_write(AD5933_I2C_WRITE); // Address the AD5933 for write.
ack_rcv = i2c_write(ADDRESSPOINTERCMD); // Write the address pointer cmd.
ack_rcv = i2c_write(address); // Write the address to request reading from.
i2c_stop(); // Stops I2C transaction.

/* Read back the byte pointed to by the above address initialization. */
i2c_start(); // Start I2C transaction.
ack_rcv = i2c_write(AD5933_I2C_READ); // Address the AD5933 for read.

/*** TEST CODE ***/

byte_rcv = i2c_read(I2C_NACK); // Receive byte and send NACK to slave.

i2c_stop(); // Stops I2C transaction.

return byte_rcv; // Return the received byte from AD5933.
}




in above code i suppose to write all three

AD5933_I2C_WRITE
ADDRESSPOINTERCMD
0x03

but before 0x03 i got slave to talk to the bus and put data in between.

so i don't know wht is goin on ... code seems rite to me as far as i2c communication is concern ... i looked on scope and logic analyzer and i got same value. so some how in between 2nd and 3rd write sequence there is some other data placed on. but i do single stepping then i doesn't have.

so if anybody has solution of this problem please let me know.

thank u.

nehal
_________________
nehal

[PCM programmer]

[nehallove]

sorry i was just testing the other address thing if i can write at all or not ... i was using address 0x8f for writing the register ... sorry my mistake ... but i got frustrated to make it work.
_________________
nehal