CM106-L+ C-Media Electronics, CM106-L+ Datasheet - Page 24

• Manufacturer Part Number: CM106-L+
• Description: USB Audio I/O Controller
• Manufacturer: C-Media Electronics

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The figure below shows typical transactions between MCU and CM106. After a START, MCU
should send 7-bit slave address (7’b0111000) first, and then the 8
when it’s high; or a write transfer when it’s low.
MCU write:
MCU read:
In a write transfer, MCU keeps acting as the transmitter. CM106F+/L+ regards the first DATA byte
as start register address. The second and third DATA bytes are the content that MCU writes to
the register addresses.
In a read transfer, two transactions are necessary. MCU resets start register address by the first
transaction. Then MCU changes to be the receiver during the second transaction to get four
bytes of data.
CM106F+/L+ supports four-wire serial EEPROM interface. When an external serial EEPROM is
detected, Vendor ID and Product ID reported within Device Descriptor will be derived from the
content of serial EEPROM. The organization of serial EEPROM is shown below:
Users can program serial EEPROM via HID interface, as described in the former section.
Although 64 words can be accessed by CM106F+/L+, only the first three words are significant to
CM106F+/L+. The first word is a magic code. Only when it matches, CM106F+/L+ will regard the
serial EEPROM valid.
Date: 08/19/2005
Byte
S
S
S
4
S
0
6.3 SERIAL EEPROM CONTENT
: From CM106 to MCU
: START condition
: Positive acknowledge
: One byte data
8’h70
8’h70
8’h71
0
0
0
Byte[0]
8’h01
8’h00
0
1
0
Address = 0
Address = 1
Address = 2
Address = 63
High End 8CH DAC and 2CH ADC Integrated Solution
P
1
Byte[1]
Byte[1]
: From MCU to CM106
: STOP condition
: Negative acknowledge
- 24 -
Product ID
0
0
16’hXXXX
Vendor ID
16’h630X
Byte[2]
Byte[2]
1
0
th
bit denotes a read transfer
P
Byte[3]
CM106-F+/L+
Version： 1.01
1
P