PCA9846

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© NXP Semiconductors N.V. 2015. All rights reserved.

Product data sheet

Rev. 1 — 9 November 2015

9 of 32

NXP Semiconductors

PCA9846

6.3 Control register

Following the successful acknowledgement of the slave address, the bus master will send

a byte to the PCA9846, which will be stored in the control register. If multiple bytes are

received by the PCA9846, it will save the last byte received. This register can be written

If more than 3 bytes are read, the slave device loops back to the first byte (manufacturer byte) and keeps sending data until the

master generates a ‘no acknowledge’.

Fig 9.

Device ID field read operation

aaa-011781

A7 A6 A5 A4 A3 A2 A1

of the device to be identified

A

no acknowledge

from master

P

STOP condition

M

11

M

10

M9 M8 M7 M6 M5 M4

Sr

repeated START

condition

1 A

R/W

S

1

1

1

1

1

0

0

Device ID address

START condition

0 A

R/W

acknowledge from

one or several slaves

0 A

don’t care

acknowledge from

slave to be identified

1

1

1

1

1

0

0

Device ID address

acknowledge from

slave to be identified

A M3 M2 M1 M0

acknowledge

from master

manufacturer name = 000000000000

P8 P7 P6 P5 A

acknowledge

from master

P4 P3 P2 P1 P0 R2 R1 R0

part identification = 100001010

revision = 000

Fig 10. Control register

002aab190

X

X

X

X

B3

B2

B1

B0

channel selection bits

(read/write)

76543210

channel 0

channel 1

channel 2

channel 3