pca9671 NXP Semiconductors, pca9671 Datasheet - Page 10

• Manufacturer Part Number: pca9671
• Description: Remote 16-bit I/o Expander For Fm+ I2c-bus With Reset
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9671_1
Product data sheet
7.2.2 Device ID (PCA9671 ID field)
The I
a ‘Software Reset Abort’. The PCA9671 does not initiate a reset of its registers.
The unique sequence that initiates a Software Reset is described in
The Device ID field is a 3-byte read-only (24 bits) word giving the following information:
The Device ID is read-only, hardwired in the device and can be accessed as follows:
1. START command.
2. The master sends the Reserved Device ID I
3. The master sends the I
4. The master sends a Re-START command.
5. The master sends the Reserved Device ID I
6. The device ID read can be done, starting with the 8 manufacturer bits (first byte +
7. The master ends the reading sequence by NACKing the last byte, thus resetting the
Fig 12. Software Reset sequence
•
•
•
8 bits with the manufacturer name, unique per manufacturer (for example,
NXP Semiconductors).
13 bits with the part identification, assigned by manufacturer, the 7 MSBs with the
category ID and the 6 LSBs with the feature ID (for example, PCA9671 16-bit
quasi-output I/O expander).
3 bits with the die revision, assigned by manufacturer (for example, Rev X).
bit set to logic 0 (write).
The LSB is a ‘Don’t care’ value. Only one device must acknowledge this byte (the one
that has the I
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 logic 1 (read).
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).
slave device state machine and allowing the master to send the STOP command.
2
C-bus master must interpret a non-acknowledge from the PCA9671 (at any time) as
S
START condition
2
C-bus slave address).
SWRST Call I
0
Rev. 01 — 20 December 2006
0
0
2
C-bus slave address of the slave device it needs to identify.
2
0
C-bus address
0
Remote 16-bit I/O expander for Fm+ I
0
acknowledge
from slave(s)
0
R/W
0
Registers are set to default power-up values.
A
0
2
2
0
C-bus address ‘1111 100’ with the R/W
C-bus address ‘1111 100’ with the R/W
SWRST data = 06h
0
0
PCA9671 is(are) reset.
0
1
acknowledge
from slave(s)
1
0
002aac281
Figure
A
PCA9671
© NXP B.V. 2006. All rights reserved.
2
P
C-bus with reset
12.
10 of 34