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LTE Standard Module Series
EC20 R2.1 Mini PCIe Hardware Design
EC20_R2.1_Mini_PCIe_Hardware_Design 21 / 51
3.6.2. COEX UART Interface*
The following table shows the pin definition of the COEX UART interface.
Table 8: Pin Definition of COEX UART Interface
1.
AT+IPR
command can be used to set the baud rate of the main UART, and
AT+IFC
command can be
used to set the hardware flow control (hardware flow control is disabled by default). Please refer to
document [2]
for details.
2.
“*” means under development.
3.7. USB Interface
EC20 R2.1 Mini PCIe provides one integrated Universal Serial Bus (USB) interface which complies with
USB 2.0 specification. It can only be used as a slave device. Meanwhile, it supports high speed (480Mbps)
mode and full speed (12Mbps) mode. The USB interface is used for AT command communication, data
transmission, GNSS NMEA output, software debugging, firmware upgrade and voice over USB.
The following table shows the pin definition of USB interface.
Table 9: Pin Definition of USB Interface
The following figure shows a reference circuit of USB interface.
Pin Name
Pin No.
I/O
Power Domain
Description
COEX_UART_RX
3
DI
1.8V
LTE/WLAN&BT coexistence signal.
It is prohibited to be pulled up to
high level before startup.
COEX_UART_TX
5
DO
1.8V
LTE/WLAN&BT coexistence signal.
It is prohibited to be pulled up to
high level before startup.
Pin Name
Pin No.
I/O
Description
Comment
USB_DM
36
IO
USB differential data (-)
Require differential impedance of 90Ω
USB_DP
38
IO
USB differential data (+)
Require differential impedance of 90Ω
NOTES