pca9674a NXP Semiconductors, pca9674a Datasheet - Page 11

• Manufacturer Part Number: pca9674a
• Description: Remote 8-bit I/o Expander For Fm+ I2c-bus With Interrupt
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Product data sheet
PCA9674_PCA9674A_2
7.2.1 Software Reset
The Software Reset Call allows all the devices in the I
state value through a specific formatted I
implies that the I
The Software Reset sequence is defined as following:
The I
time) as a ‘Software Reset Abort’. The PCA9674/74A does not initiate a reset of its
registers.
The unique sequence that initiates a Software Reset is described in
1. A START command is sent by the I
2. The reserved General Call I
3. The PCA9674/74A device(s) acknowledge(s) after seeing the General Call address
4. Once the General Call address has been sent and acknowledged, the master sends
5. Once the right byte has been sent and correctly acknowledged, the master sends a
Fig 10. Device ID address
Fig 11. Software Reset sequence
is sent by the I
‘0000 0000’ (00h) only. If the R/W bit is set to 1 (read), no acknowledge is returned to
the I
1 byte. The value of the byte must be equal to 06h.
a. The PCA9674/74A acknowledges this value only. If the byte is not equal to 06h, the
If more than 1 byte of data is sent, the PCA9674/74A does not acknowledge any
more.
STOP command to end the Software Reset sequence: the PCA9674/74A then resets
to the default value (power-up value) and is ready to be addressed again within the
specified bus free time. If the master sends a Repeated START instead, no reset is
performed.
2
C-bus master must interpret a non-acknowledge from the PCA9674/74A (at any
PCA9674/74A does not acknowledge it.
2
C-bus master.
2
S
START condition
C-bus is functional and that there is no device hanging the bus.
2
SWRST Call I
C-bus master.
0
Rev. 02 — 12 October 2006
0
0
2
0
Remote 8-bit I/O expander for Fm+ I
C-bus address
1
0
2
C-bus address ‘0000 000’ with the R/W bit set to 0 (write)
0
1
acknowledge
from slave(s)
0
1
2
R/W
C-bus master.
0
2
Registers are set to default power-up values.
C-bus command. To be performed correctly, it
1
A
0
1
0
SWRST data = 06h
0
0
PCA9674/74A is(are) reset.
002aac116
2
0
0
C-bus to be reset to the power-up
R/W
0
PCA9674/74A
1
acknowledge
from slave(s)
1
0
002aac262
2
C-bus with interrupt
Figure
A
© NXP B.V. 2006. All rights reserved.
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