Smart LTE Module Series
SC650T Hardware Design
SC650T_Hardware_Design 49 / 131
important to route the USB differential traces in inner-layer with ground shielding on not only upper
and lower layers but also right and left sides.
Keep the ESD protection devices as close as possible to the USB connector.
Make sure the trace length difference between USB 2.0 DM/DP differential pair and that between
USB 3.0 RX/TX differential pairs both do not exceed 0.7mm.
Table 9: USB Trace Length Inside the Module
Pin No.
Signal
Length (mm)
Length Difference (DP-DM)
33
USB_DM
40.02
-0.04
32
USB_DP
39.99
171
USB_SS_RX_P
27.89
0.01
172
USB_SS_RX_M
27.90
174
USB_SS_TX_P
21.51
0.91
175
USB_SS_TX_M
22.42
3.10. UART Interfaces
The module provides the following four UART interfaces:
UART5:
4-wire UART interface, hardware flow control supported, 1.8V power domain
UART6:
2-wire UART interface,
UART2:
2-wire UART interface, used for debugging
UART4:
2-wire UART interface
The following table shows the pin definition of UART interfaces.
Table 10: Pin Definition of UART Interfaces
Pin Name
Pin No.
I/O
Description
Comment
UART2_TXD
5
DO
UART2 transmit data.
Debug port by default.
1.8V power domain.
If unused, keep these pins
open.
UART2_RXD
6
DI
UART2 receive data.
Debug port by default.
