Quectel EG915U-EU - UART Interface

LTE Standard Module Series
EG915U-EU_Hardware_Design 46 / 81
The following figure shows a reference design of PCM interface with external codec IC.
PCM_DIN
PCM_DOUT
PCM_SYNC
PCM_CLK
I2C_SCL
I2C_SDA
Module
4.7K 4.7K
BCLK
LRCK
DAC
ADC
SCL
SDA
BIAS
MICBIAS
INP
INN
LOUTP
LOUTN
Codec
1.8 V
External 26MHz Crystal
0R
MCLK
Figure 22: Reference Circuit of PCM Application with Audio Codec
4.6. UART Interface
The module provides 3 UART interfaces and the following shows their features:
⚫ The main UART interface supports 4800 bps, 9600 bps, 19200 bps, 38400 bps, 57600 bps, 115200
bps, 230400 bps, 460800 bps and 921600 bps baud rates, and the default is 115200 bps. This
interface is used for data transmission and AT command communication.
⚫ The debug UART interface supports 921600 bps baud rate. It is used for the output of partial logs.
⚫ Auxiliary UART.
The following tables show the pin definition of main UART interface.
Pin definition of the UART interface is here as follows:
Table 16: Pin Definition of UART Interface
Pin Name
Pin No.
I/O
Description
Comment
MAIN_CTS
36
DO
Main UART clear to send
1.8 V power domain
MAIN_RTS
37
DI
Main UART request to send
MAIN_RXD
34
DI
Main UART receive