CS4341 Datasheet, PDF (26/36 Pages) Cirrus Logic – 24-Bit, 96 kHz Stereo DAC with Volume Control

CS4341
Control function can enable the system designer to
achieve idle channel noise/signal-to-noise ratios
which are only limited by the external mute circuit.
7. CONTROL PORT INTERFACE
The control port is used to load all the internal set-
tings of the CS4341. The operation of the control
port may be completely asynchronous to the audio
sample rate. However, to avoid potential interfer-
ence problems, the control port pins should remain
static if no operation is required. *
The control port has 2 modes: SPI and I²C compat-
ible, with the CS4341 operating as a slave device in
both modes. If I²C operation is desired, AD0/CS
should be tied to VA or AGND. If the CS4341 ever
detects a high to low transition on AD0/CS after
power-up, SPI mode will be selected. The control
port registers are write-only in SPI mode.
7.1 SPI Mode
In SPI mode, CS is the CS4341 chip select signal,
CCLK is the control port bit clock, CDIN is the in-
put data line from the microcontroller and the chip
address is 0010000. All signals are inputs and data
is clocked in on the rising edge of CCLK.
Figure 7 shows the operation of the control port in
SPI mode. To write to a register, bring CS low. The
first 7 bits on CDIN form the chip address, and
must be 0010000. The eighth bit is a read/write in-
dicator (R/W), which must be low to write. The
next 8 bits form the Memory Address Pointer
(MAP), which is set to the address of the register
that is to be updated. The next 8 bits are the data
which will be placed into the register designated by
the MAP.
The CS4341 has MAP auto increment capability,
enabled by the INCR bit in the MAP register. If
INCR is 0, then the MAP will stay constant for suc-
cessive writes. If INCR is set to 1, then MAP will
auto increment after each byte is written, allowing
block reads or writes of successive registers.
7.2 I²C Compatible Mode
In I²C compatible mode, SDA is a bi-directional
data line. Data is clocked into and out of the part by
the clock, SCL, with the clock to data relationship
as shown in Figure 8. There is no CS pin. Pin AD0
forms the partial chip address and should be tied to
VA or AGND as required. The upper 6 bits of the
7-bit address field must be 001000. To communi-
cate with the CS4341 the LSB of the chip address
field, which is the first byte sent to the CS4341,
should match the setting of the AD0 pin. The eighth
bit of the address byte is the R/W bit (high for a
read, low for a write). If the operation is a write, the
next byte is the Memory Address Pointer, MAP,
which selects the register to be read or written. The
MAP is then followed by the data to be written. If
the operation is a read, then the contents of the reg-
ister pointed to by the MAP will be output after the
chip address.
The CS4341 has MAP auto increment capability,
enabled by the INCR bit in the MAP register. If
INCR is 0, then the MAP will stay constant for suc-
cessive writes. If INCR is set to 1, then MAP will
auto increment after each byte is written, allowing
block reads or writes of successive registers.
For more information on I²C, please see “The I²C-
Bus Specification: Version 2.0”, listed in the Ref-
erences section.
* The MCLK is required for both control port inter-
faces.
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DS298PP2