CM108B Datasheet, PDF (18/24 Pages) C-Media Electronics – A Highly Integrated USB Audio Single Chip

1: volume-down button pressed
0
R
0: volume-up button released
1: volume-up button pressed
CM108B
USB Audio Single Chip
0x0
HID_IR1 (HID input report byte 1)
Offset: 0x01
Bits
Read/Write
Description
When HID_IR0[7:6] == 2’b00: HID_IR1[3:0] is the input from
7-0
R
GPIO4 ~ GPIO1 in input mode
When HID_OR0[7] == 1’b1: mapped from EEPROM_DATA0
HID_IR2 (HID input report byte 2)
Offset: 0x02
Bits
Read/Write
Description
7-0
R
When HID_OR0[7] == 1’b1: mapped from EEPROM_DATA1
Default
0x00
Default
0x00
HID_IR3 (HID input report byte 3)
Offset: 0x03
Bits
Read/Write
Description
7-0
R
When HID_OR0[7] == 1’b1: mapped from EEPROM_CTRL
Default
0x00
HID_OR0 (HID output report byte 0)
Offset: 0x04
Bits
Read/Write
Description
Default
0: HID_OR1-2 are used for GPO; HID_OR0, 3 are used for SPDIF
1: reserved
7-6
R / W 2: values written to HID_OR0-3 are also mapped to
0x0
EEPROM_DATA0-1, EEPROM_CTRL (See Note)
3: reserved
5
R / W Reserved
0x0
4
R/W
When HID_OR0[7] == 1’b0: valid bit in SPDIF frame
When HID_OR0[7] == 1’b1: reserved
0x0
3-0
R/W
When HID_OR0[7] == 1’b0: first nibble of SPDIF status channel
When HID_OR0[7] == 1’b1: reserved
0x0
Note 1: When EEPROM access is done, HID interrupt will occur. USB host can get the result from interrupt pipe
(endpoint 3).
Note 2: HID_OR0 is used for SPDIF when SPDIF_CONFIG[5] == 1’b0
HID_OR1 (HID output report byte 1)
Offset: 0x05
Bits
Read/Write
Description
When HID_OR0[7:6] == 2’b00: HID_OR1[3:0] is the output to
GPIO4 ~ GPIO1 in output mode
7-0
R/W
0: GPO drives L
1: GPO drives H
When HID_OR0[7:6] == 2’b01: reserved
When HID_OR0[7:6] == 2’b1x: mapped to EEPROM__DATA0
HID_OR2 (HID output report byte 2)
Offset: 0x06
Default
0x00
Datasheet Revision: 1.11
Page 18 / 24
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