CM6308 C-Media Electronics, Inc., CM6308 Datasheet - Page 24

• Manufacturer Part Number: CM6308
• Description: Cm6308 Usb Audio Chip Specification
• Manufacturer: C-Media Electronics, Inc.

Date: 09/04/2007
In order for our SPI interface to be capable of interfacing with all codecs, the content of the data
registers (address offset 9Bh-99h, which includes address, r/w, and data bits) that are written to
or read from the codec are not translated by the hardware SPI interface, but by the system
driver. The meaning of the bits in this register should be interpreted according to the individual
codec.
Fig. D. An SPI 2-byte write transaction with codec latching data at spi_clk high state.
Fig. E. An SPI 2-byte read transaction with codecs latching data at spi_clk low state.
SPI 2-byte Read Transaction (R/W bit is embedded in spi_data_o[15:8],
spi_cen
spi_clk
spi_data_o
spi_data_i
spi_cen
spi_clk
spi_data_o
spi_data_i
SPI 2-byte Write Transaction
MSB
MSB
15 14 13 12 11 10
15 14 13 12 11 10
data in address offset 9Ah
The bit length of the high
impedance is dependent on
the individual codec.
data in address offset B0h
High impedance
R/W bit is somewhere between bit15~bit8,
depending on different codecs
High impedance
but this bit position is dependent on codecs)
9
-
LSB
24/42 -
9
8
8
MSB
CMI8788 latch data at spi_clk=0
7
codec latch data at spi_clk = 1
This line is not fixed. It can be moved to
the left or right depending on codecs
7
data will be captured in
address offset B1h
6
data in address offset B1h
6
5
Don’t care
5
4
Audio and Voice Applications
Single-Chip USB Solution for
4
3
2
3
1
2
LSB
0
1
LSB
0
CM6308
Version: