Doc. No: Unex-QSG-21-003
19/30
A printed version of this document is an uncontrolled copy
© 2023 Unex Technology Corporation – Company Confidential
Switching of internal/external GNSS and 1PPS signal is not controlled by DIP switch.
for detailed instruction.
Table 11: DIP Switch Functions
Position
Name
ON Function
OFF Function
SW1.1
5V_SW
5V power from mPCIe
5V power from cable, or
3.3V single voltage mode
SW1.2
RXD_SW
UART RXD from mPCIe
UART RXD from cable
SW1.3
TXD_SW
UART TXD from mPCIe
UART TXD from cable
SW1.4
EX_RSTn_SW CRATON2 reset from mPCIe
CRATON2 reset from cable
SW1.5
1PPS_SW
External 1PPS from mPCIe
External 1PPS from cable
SW1.6
TAMPER#_SW TAMPER# from mPCIe
TAMPER# from cable
SW1.7
TRIGGER_SW
Trigger when tamper SW
close to ground (1KΩ PU)
Trigger with tamper SW
open from 3.3V (32KΩ PD)
SW1.8
BOOT_SW
Boot from NAND
Boot from USB0 (DFU)
9.
Design-in Guidelines
The SOM-352 pinout is compatible with most standard PCIe mini card interfaces.
However, it may need to be fed with 5V DC power and connecting other I/O interfaces
through an external cable when installed on an existing mPCIe system board. A customized
PCIe mini card pinout can help user to get rid of the extra cable and to rely on the PCIe
mini card interface alone. A design-in system board solution may provide improved
reliability, simpler installation, and cost saving to the overall system.
9.1.
Power Line Traces
•
Power line traces should be as wide as possible, in order to reduce impedance of
these lines.
•
Crossing by any other lines of upper or lower layer should also be avoided.
•
The maximum power consumption occurs during RF transmission. A typical
transmitting frame lasts 1-2ms.
•
It is recommended to keep the 5V supply current no less than 2A (continuous) to
keep RF performance from degradation.
•
If the SOM-352 halts or resets while performing a V2X RF transmission, it is
recommended to add a bulk capacitor on the 5V trace near the mPCIe connector to
