ISD3900
Publication Release Date: Dec 10, 2013
- 52 -
Revision 1.5
CFG15 Configuration Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
VOLA[7:0]
Default 0x00:
0 dB attenuation to the volume control coming from the I
2
S or ADC.
Configuration register CFG15 controls the volume level coming from the I
2
S or ADC input. Setting 0
has 0dB attenuation. Each subsequent step provides 0.25dB of attenuation.
Table 12-43 CFG16 Register.
CFG16 Configuration Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
AGC_GAIN[-1:-3]
INC
DEC
FAST_DEC
HOLD
NOISE
This is a read-only register that provides information on the performance of the AGC:
NOISE
– High if noise gate is active.
HOLD -
High if AGC gain hold is active.
FAST_DEC
– High if peak signal level is >90% causing a fast decrement of gain.
DEC
– High if peak signal level is > 81.25%FS causing a decrement of gain.
INC
- High if peak signal level is less than 80%FS causing gain to increment unless HOLD or
NOISE is active.
AGC_GAIN[-1:-3]
– Additional bits of resolution of AGC_GAIN setting of CFGE.
Table 12-44 CFG17 Register
CFG17 Configuration Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
PLL_LOCK
RB_SPI
I
2
S_MM
I
2
S_ATT
DECODE
COMP_ACTIVE
UPDATE
IMM
Default 0x01:
Turn off double buffering of configuration. Configuration is updated after each register byte is
written.
Disable the 3dB attenuation when left and right channel are mixed.
I
2
S slave mode: ISD3900 accepts SCK and WS from a bus master.
Monitor the RDY/BSYB handshake through the hardware pin.
Configuration register CFG17 controls how the configuration registers are applied: