26

DS861PP1

CS5346

dress and set the read/write bit (R/W) high. The next falling edge of CCLK will clock out the MSB of the

addressed register (CDOUT will leave the high-impedance state).

For both read and write cycles, the memory address pointer will automatically increment following each

data byte in order to facilitate block reads and writes of successive registers.

5.7.2

I²C Mode

In I²C Mode, SDA is a bidirectional data line. Data is clocked into and out of the part by the clock, SCL.

There is no CS pin. Pins AD0 and AD1 form the two least-significant bits of the chip address and should

be connected through a resistor to VLC or DGND as desired. The state of the pins is sensed while the

CS5346 is being reset.

The signal timings for a read and write cycle are shown in Figure 15 and Figure 16. A Start condition is

defined as a falling transition of SDA while the clock is high. A Stop condition is a rising transition while

the clock is high. All other transitions of SDA occur while the clock is low. The first byte sent to the CS5346

after a Start condition consists of a 7-bit chip address field and a R/W bit (high for a read, low for a write).

The upper 5 bits of the 7-bit address field are fixed at 10011. To communicate with a CS5346, the chip

address field, which is the first byte sent to the CS5346, should match 10011 followed by the settings of

the AD1 and AD0. The eighth bit of the address is the R/W bit. If the operation is a write, the next byte is

the Memory Address Pointer (MAP) which selects the register to be read or written. If the operation is a

read, the contents of the register pointed to by the MAP will be output. Following each data byte, the mem-

ory address pointer will automatically increment to facilitate block reads and writes of successive regis-

ters. Each byte is separated by an acknowledge bit. The ACK bit is output from the CS5346 after each

input byte is read, and is input to the CS5346 from the microcontroller after each transmitted byte.

MA P

MSB

LSB

DATA

by te 1

by te n

R/W

R/W

AD D R ES S

CH IP

ADDRESS

CHIP

CD IN

CC L K

CS

CD OU T

MSB

LSB MSB

LSB

1001111

1001111

MAP = Memory Address Pointer, 8 bits, MSB first

High Impedance

Figure 14. Control Port Timing in SPI Mode

4

5

6

7

24 25

SCL

CHIP ADDRESS (WRITE)

MAP BYTE

DATA

DATA +1

START

ACK

STOP

ACK

ACK

ACK

1

0

0

1

1 AD1 AD0 0

SDA

6

6

5

4

3

2

1

0

7

6

1

0

7

6

1

0

7

6

1

0

0

1

2

3

8

9

12

16 17 18

19

10 11

13 14 15

27 28

26

DATA +n

Figure 15. Control Port Timing, I²C Write