CM119B
USB Audio Single Chip
6 Function Description
6.1 Content Format for EEPROM (93C46)
The CM119B integrates USB transceiver, internal oscillator and regulator so that only several passive components are
necessary for the USB interface connection. Default USB descriptors are embedded in the CM119B; therefore there is
no additional design effort needed for a generic USB operation. For customized product, customer can attach a SPI
interface 93C46 EEPROM to override the embedded VID, PID and initial/max/min volume settings. The CM119B
automatically detects 93C46 existence and performs the overwrite function during power up.
Each address has 2-byte data, prefix `0x` means hex number
Address(Hex)
Description
bit[15:4] Magic Word
0x670X where X = bit 4, 3, 2, 1
bit[3] The value within address 0x2A, 0x2B, 0x32 is valid 1: valid 0: invalid
bit[2] reserved, should be 1
0x00
bit[1] serial number enable control 1: enable, 0: disable(default)
bit[0] reserved, should be 1
0x01
0x02
VID 2-byte
PID 2-byte
Serial number 1st
byte
(bit15-bit8,
character)
Serial number length
first (bit7-bit0)
0x03
0x04
~
Serial number 12-byte
0x09
Product string 1st
byte (bit15-bit8, first
character)
Product string length
(bit7-bit0) [0x3E->30,0x40->31Char]
0x0A
0x0B
~
Product string 30-byte (default: USB Audio Device)
0x19
Manufacturer string
1st byte
(bit15-bit8,
character)
Manufacturer string length
first (bit7-bit0) [0x3E->30,0x40->31Char]
0x1A
0x1B
~
Manufacturer string 30-byte (default: C-Media Electronics Inc.)
0x29
bit[15: 9] DAC initial volume (7-bit, default = -10dB)
bit[8: 3] ADC initial volume (6-bit, default = 8dB)
bit[2] DAC EEPROM MAX/MIN volume valid
bit[1] ADC EEPROM MAX/MIN volume valid
bit[0] AA EEPROM MAX/MIN volume valid
bit[15:11] AA initial volume (5-bit, default = -7dB)
bit[10] Reserved, should be 0
bit[9] Boost mode 0: 22dB 1:12dB (default)
bit[8] Reserved, should be 0
bit[7] Total Power Control 1:enable, 0:disable(default)
bit[6] Reserved, should be 0
0x2A
0x2B
bit[5] MIC High Pass Filter
bit[4] MIC PLL Adjust
bit[3] MIC BOOST
1:enable(default), 0:disable
1:enable, 0:disable(default)
1:enable (default), 0:disable
bit[2] DAC Output Terminal property set to SPK or HP
1: Headset, 0: Speaker(default) bit[1] HID,
1: enable (default), 0: disable
bit[0] Remote wakeup, 1:enable, 0:disable(default)
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Revised: Aug. 2013 Copyright© C-Media Electronics Inc.
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