5G Module Series
RG255C-GL_Mini_PCIe_Hardware_Design 26 / 57
Table 10: Pin Definition of Main UART
The signal level of main UART is 3.3 V. When connecting to MCU, you need to pay attention to the signal
direction. The reference circuit is shown as below:
MCU
TXD
RXD
RXD
TXD
RTS
CTS
RTS
CTS
GND
Module
GND
Voltage level: 3.3 V
Voltage level: 3.3 V
Figure 8: Reference Circuit of Power Supply
⚫
AT+IPR
can be used to set the baud rate of the main UART, and
AT+IFC
can be used to set the hardware
flow control (hardware flow control is disabled by default). See
document [3]
4.4. PCM
*
and I2C Interfaces
RG255C-GL Mini PCIe provides one Pulse Code Modulation (PCM) digital interface and one I2C
interface.
Pin Name
Pin No.
I/O
Description
Comment
RXD
11
DI
Receive
3.3 V power domain.
TXD
13
DO
Transmit
3.3 V power domain.
CTS
23
DI
Clear to send signal to the module
3.3 V power domain.
RTS
25
DO
Request to send signal from the
module
3.3 V power domain.
NOTE
