CS8406-CS datasheet(19/43 Pages) CIRRUS

19 / 43 page

CS8406

DS580F1

CONTROL PORT DESCRIPTION

The control port is used to access the registers, allowing the CS8406 to be configured for the

desired operational modes and formats. The operation of the control port may be completely

asynchronous with respect to the audio sample rates. However, to avoid potential interference

problems, the control port pins should remain static if no operation is required.

The control port has 2 modes: SPI and I²C, with the CS8406 acting as a slave device. SPI mode

is selected if there is a high to low transition on the AD0/CS pin, after the RST pin has been

brought high. I²C mode is selected by connecting the AD0/CS pin through a resistor to VL or

GND, thereby permanently selecting the desired AD0 bit address state.

6.1.

SPI Mode

In SPI mode, CS is the CS8406 chip select signal, CCLK is the control port bit clock (input into

the CS8406 from the microcontroller), CDIN is the input data line from the microcontroller, CD-

OUT is the output data line to the microcontroller. Data is clocked in on the rising edge of CCLK

and out on the falling edge.

Figure 9 shows the operation of the control port in SPI mode. To write to a register, bring CS low.

The first seven bits on CDIN form the chip address and must be 0010000. The eighth bit is a

read/write indicator (R/W), which should be low to write. The next eight bits form the Memory Ad-

dress Pointer (MAP), which is set to the address of the register that is to be updated. The next

eight bits are the data which will be placed into the register designated by the MAP. During writes,

the CDOUT output stays in the Hi-Z state. It may be externally pulled high or low with a 47 k

Ω

resistor, if desired.

There is a MAP auto increment capability, enabled by the INCR bit in the MAP register. If INCR

is a zero, the MAP will stay constant for successive read or writes. If INCR is set to a 1, the MAP

will autoincrement after each byte is read or written, allowing block reads or writes of successive

registers.

To read a register, the MAP has to be set to the correct address by executing a partial write cycle

which finishes (CS high) immediately after the MAP byte. The MAP auto increment bit (INCR)

may be set or not, as desired. To begin a read, bring CS low, send out the chip address and set

MA P

MSB

LSB

DATA

byte 1

by te n

R/W

A DDRE S S

CHIP

ADDRESS

CHI P

CD I N

CCL K

CD O UT

MSB

LSB MSB

LSB

0010000

MAP = Memory Address Pointer, 8 bits, MSB first

High Impedance

Figure 9. Control Port Timing in SPI Mode

CS8406-CS Arkusz danych(PDF) 19 Page - Cirrus Logic

CS8406-CS Arkusz danych(HTML) 19 Page - Cirrus Logic

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

Arkusz danych Pobierz

Link URL