Product Info

Automotive Module Series
AG35 Hardware Design
AG35_Hardware_Design 59 / 129
1. By default, I2C1 is used for codec configuration while I2C2 is not available with any codec
configuration driver.
2. When the built-in codec is used, its 8-bit address is 0x31 when reading and 0x30 when writing. In
order to avoid conflicts, please avoid using I2C1 peripherals with the same addresses.
3. When the built-in codec is used, pin 152 and pins 65~68 will not be used.
Clock and mode can be configured by AT command, and the default configuration is master mode using
short frame synchronization format with 2048kHz PCM_CLK and 8kHz PCM_SYNC. Please refer to
document [2] about AT+QDAI command for details.
The following figure shows a reference design of PCM interface with external codec IC.
PCM_IN
PCM_OUT
PCM_SYNC
PCM_CLK
I2C_SCL
I2C_SDA
Module
1.8V
2.2K 2.2K
BCLK
LRCK
DAC
ADC
SCL
SDA
BIAS
MICBIAS
INP
INN
LOUTP
LOUTN
Codec
Figure 27: Reference Circuit of PCM Application with Audio Codec
1. It is recommended to reserve an RC (R=22Ω, C=22pF) circuit on the PCM lines, especially for
PCM_CLK.
2. AG35 works as a master device pertaining to I2C interface.
I2C2_SCL
74
DO
I2C2 serial clock
Require external pull-up to 1.8V
NOTES
NOTES