Adc Function - Quectel UC20 Manual

The following figure shows the reference design of PCM interface with external codec IC.
PCM_CLK
PCM_SYNC
PCM_OUT
I2C_SCL
I2C_SDA
Module
Figure 30: Reference Circuit of PCM Application with Audio Codec
NOTES
1. It is recommended to reserved RC (R=22Ω, C=22pF) circuit on the PCM lines, especially for
PCM_CLK.
2. UC20 work as a master device pertaining to I2C interface.

3.14. ADC Function

The module provides two analog-to-digital converters (ADC) to digitize the analog signal to 15-bit digital
data such as battery voltage, temperature and so on. Using AT command AT+QADC=0 can read the
voltage value on ADC0 pin. Using AT command AT+QADC=1 can read the voltage value on ADC1 pin.
For more details of these AT commands, please refer to document [1].
In order to improve the accuracy of ADC, the trace of ADC should be surrounded by ground.
Table 17: Pin Definition of the ADC
Pin name Pin NO.
ADC0 45
ADC1 44
UC20_Hardware_Design
PCM_IN
1.8V
Description
General purpose analog to digital converter.
General purpose analog to digital converter.
MIC_BIAS
MCLK
BCLK
FS
DACIN
ADCOUT
SCLK
SDIN
NAU8814
Confidential / Released
UMTS/HSPA Module Series
UC20 Hardware Design
MIC+
MIC-
SPKOUT+
SPKOUT-
50 / 84