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Use of I2CxCCNT register in ADuC7xxx

Question asked by Sapna on Jun 20, 2014
Latest reply on Jul 11, 2014 by Sapna


I have gone through the AN-895 APPLICATION NOTE explaining I2C, still I'm not able to get a clear picture on the use of I2CxCCNT register.How to know what value to be assigned into it?

The datasheet simply explains it as :

I2CxCCNT are 8-bit start/stop generation counters. They hold off SDA low for start and stop conditions.


In the application note, an example code sequence is given:


I2C0CCNT = 0x0; // Sets Start/Stop condition counter value to 0 - minimum value.

I2C0ADR = 0xA0; // Write sequence

I2C0MTX = 0x7; // Load the Tx FIFO

while ((I2C0FSTA & 0x30) != 0x00) {} // Wait for the Tx FIFO to empty

I2C0CNT = 0x1; // Read 2 bytes from the slave

I2C0ADR = 0xA1; // Send out the Read condition

I2C0CCNT = 0x80; // Set the Start/Stop counter to a nonzero value to re-enable the Stop Condition


I understand, assigning 0x0 to the register assigns the counter to a minimum value, but what does this actually indicate? Is this a START condition?

And what does the other values indicate?

How do we issue a START or STOP condition?


Expecting help on this area. I am new to programming using I2C.

Thanks in advance.