Pcm And I2C Interfaces - Quectel EG91 Series Hardware Design

MCU/ARM
NOTE
1. Transistor circuit solution is not suitable for applications with high baud rates exceeding 460 kbps.
2. Please note that the CTS and RTS pins of the hardware flow control for the UART port are directly
connected, and pay attention to the input and output directions.

3.12. PCM and I2C Interfaces

EG91 series module provides one Pulse Code Modulation (PCM) digital interface for audio design, which
supports the following modes and one I2C interface:
 Primary mode (short frame synchronization, works as both master and slave)
 Auxiliary mode (long frame synchronization, works as master only)
In primary mode, the data is sampled on the falling edge of the PCM_CLK and transmitted on the rising
edge. The PCM_SYNC falling edge represents the MSB. In this mode, the PCM interface supports
256 kHz, 512 kHz, 1024 kHz or 2048 kHz PCM_CLK at 8 kHz PCM_SYNC, and also supports 4096 kHz
PCM_CLK at 16 kHz PCM_SYNC.
In auxiliary mode, the data is also sampled on the falling edge of the PCM_CLK and transmitted on the
rising edge. The PCM_SYNC rising edge represents the MSB. In this mode, the PCM interface operates
with a 256 kHz, 512 kHz, 1024 kHz or 2048 kHz PCM_CLK and an 8 kHz, 50 % duty cycle PCM_SYNC.
EG91_Series_Hardware_Design
VDD_EXT
TXD
RXD
10K
VCC_MCU
RTS
CTS
GPIO
EINT
GPIO
GND
Figure 21: Reference Circuit with Transistor Circuit
4.7K
VDD_EXT
1 nF
10K
1 nF
VDD_EXT
4.7K
LTE Standard Module Series
Module
RXD
TXD
RTS
CTS
DTR
RI
DCD
GND
49 / 105