NXP Semiconductors PCA9665 - Manual (Page 52)

PCA9665_2 © NXP B.V. 2006. All rights reserved.
Product data sheet Rev. 02 — 7 December 2006 52 of 91
NXP Semiconductors
PCA9665
Fm+ parallel bus to I 2 C-bus controller
In Buffered Receiver mode, when an interrupt is generated and SI is set to 1 (after a
STOP command or a buffer full condition), the buffer pointer is reset and points at the first
received data byte. Reading the I2CCOUNT register then indicates the number of bytes
that have been sent or received (BC[6:0]). Reading of the data from I2CDAT buffer can
then be initiated starting with the first received byte.
Table 42. I2CCOUNT register value based on the performed operation
Operation performed I2CCOUNT register value
Master Transmitter Buffered mode
After START condition don’t care
After Slave Address Sent + ACK bit received and interrupt received 1
After Slave Address Sent + NACK bit received 1
After Slave Address Sent + ‘n’ data bytes sent, ACK bit received, both
address and ‘n’ data n + 1
After Slave Address Sent + ‘n’ data bytes sent, last byte n + 1
After STOP don’t care
After losing arbitration in Slave Address + W and addressed as slave 0
After losing arbitration in slave address + W and not addressed as slave 0
After losing arbitration in data at n th byte n (if there was no interrupt after slave address was
sent)
n − 1 (if there was an interrupt after slave address
was sent)
Master Receiver Buffered mode
After START condition don't care
After Slave Address Sent + ACK bit received don't care (because no interrupt received here)
After Slave Address Sent + NACK bit received 1
After Slave Address Sent + ‘n’ data bytes received, ACK bit received for
address and ACK bit returned for ‘n’ data bytes n
After Slave Address Sent + ‘n’ data bytes received, NACK bit returned
for the last byte n
After STOP don't care
After losing arbitration in Slave Address + R bit and addressed as slave 0
After losing arbitration in slave address + R and not addressed as slave 0
After losing arbitration in ACK of n th byte n
Slave Receiver Buffered mode (regular slave mode and General Call response
After Slave Address + W and ACK bit returned for slave address (both in
regular mode and when PCA9665 loses arbitration and is addressed as
slave) 0
After receiving ‘n’ bytes, ACK bit returned for the ‘n’ bytes n
After receiving ‘n’ bytes, NACK bit returned for the last byte n
Slave Transmitter Buffered mode
After Slave Address + R and ACK bit returned for slave address (both in
regular mode and when PCA9665 loses arbitration and is addressed as
slave) 0
After ‘n’ data bytes transmitted and ACK bit received for ‘n’ bytes n
After ‘n’ data bytes transmitted and NACK bit received for the last byte n