PCA9673_1

© NXP B.V. 2007. All rights reserved.

Product data sheet

Rev. 01 — 1 February 2007

9 of 33

NXP Semiconductors

PCA9673

The Device ID is read-only, hardwired in the device and can be accessed as follows:

1. START command

bit set to 0 (write).

The LSB is a ‘Don’t care’ value. Only one device must acknowledge this byte (the one

4. The master sends a Re-START command.

Remark: A STOP command followed by a START command will reset the slave state

machine and the Device ID read cannot be performed.

Remark: A STOP command or a Re-START command followed by an access to

another slave device will reset the slave state machine and the Device ID read cannot

be performed.

bit set to 1 (read).

6. The device ID read can be done, starting with the 8 manufacturer bits (first byte +

4 MSB of the second byte), followed by the 13 part identification bits and then the

3 die revision bits (3 LSB of the third byte).

7. The master ends the reading sequence by NACKing the last byte, thus resetting the

slave device state machine and allowing the master to send the STOP command.

Remark: The reading of the Device ID can be stopped anytime by sending a NACK

command.

Remark: If the master continues to ACK the bytes after the third byte, the PCA9673

rolls back to the first byte and keeps sending the Device ID sequence until a NACK

has been detected.

For the PCA9673, the Device ID is as shown in Figure 13.

Fig 13. PCA9673 ID

0

002aac333

0

0

revision

0

0

1

0

0

0

1

0

0

part identification

0

0

0

0

0

0

0

0

0

0

0

0

manufacturer

category identification

feature identification