Pinout

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Pin Descriptions

Pin Number	BCM Pin	Pin Name	Description
8	UART_TX	PCI RX	This pin functions as the serial data input to the module for UART communication.
10	UART_RX	PCI TX	This pin functions as the serial data output from the module for UART communication
13	GPIO27	USER LED	Active HIGH, to switch on the USER LED, the pin's state should be HIGH.
15	GPIO22	USER BUTTON	This pin normally pulled-down to ground. When the button is pressed, pin switches to LOW.
31	GPIO6	RI	This pin is Ring indicator functions as the indication for receiving call or SMS, can be calibrated to HIGH or LOW using the AT commands.
33	GPIO13	DTR	When the module is in sleep mode, DTR pin allows to wake the module up by pulling it to LOW.
35	GPIO19	W_DISABLE	This pin is used to turn Airplane Mode on the module, by pulling it HIGH.
37	GPIO26	HAT_PWR_OFF	Power regulator control. Normally pulled-down, when this pin drove to HIGH, Hat's power will cut off.

Layout

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Compatible Mini PCIe Modules

Manufacturer	Module
Quectel	EC25, LTE-EP06, EC21 , EC20 Mini PCIe LTE IoT Module, UC20 , LTE-EP06
Telit	LM960, LE910V2, HE910,LE910C1, LE910C4, and more
Thales	PLS62W, mPLS8, mPLAS9
Sierra	AirPrime MC Series
Huawei	ME909s-120, ME909s-821, and more
Simcom	SIM7100, SIM7230, and more
ZTE	ZM8620, and more
U-Blox	MPCI-L2 Series

If one is looking to use different mini PCIe modules other than the ones mentioned above, it should be compared with the pinout of mini PCIe below. The following mentioned pins are connected to the Base HAT.

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Compatible Boards

Raspberry Pi 4, 3, 2, B+, A+, Zero i.e. RPi which contains 40W GPIO header.
Asus Tinker Board
Rock 64*
Orange Pi*
Samsung ARTIK’s Eagleye board*
Latte Panda

Note 1: The Base HAT doesn't need or has a driver. Rather The host computer(such as RPi, Asus Tinker Board) needs the driver of the compatible module that will be used with the Base HAT. For example, if you are using Quectel's EC25 with the Base HAT, then your host device should have the driver for Quectel EC25. Nowadays, most of the Linux kernel comes with the required drivers installed as a result the modules are recognized.

Note 2: These compatibility list created by assuming you’ve connected the Base HAT to the device via USB. UART communication can be work with every device in the list easily which has 3.3V level UART port.

Warning: For the best working condition, power the Raspberry Pi with a minimum 2 Amps 5V adapter while using the Base HAT attached. We don’t recommend the usage of long and low-quality micro USB cables between Base Shield and Raspberry Pi. It causes data and power loss. Thus, the cable included the package works greatly.

Dimension

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LEDs

PWR LED: When the module is powered up, this RED led turns on
SGNL LED: This BLUE led indicates the status of the connection. When the connection is established and data is being transmitted/received, this led will blink at special intervals. Otherwise, if there is no connection, the led will remain off.
USER LED: It is a programmable user-led can be controlled from the GPIO27 of Raspberry Pi for debugging or just fun.

Buttons

User Button: It is a programmable user button that is connected to GPIO22. Reads HIGH by default.

Solder Jumper(SJ)

When you observe the HAT, you will come across some solder Jumpers marked as SJx (SJ1, SJ2, SJ3, etc). These solder jumpers are either connected or disconnected by default. These can be used to enable or disable the default use case. These SJ are provided for the cases where the specific GPIO are conflicting with the users requirement. Disconnecting the jumpers may lead to loss in some programmable feature. For instance, Cutting the SJ4 trace which is RI, Ring Indicator used as indication for call or SMS cannot be used.

Disconnecting: Cut the narrow trace between the middle of these solder jumper with a utility knife.
Connecting/Reconnecting: Solder the jumper to connect the traces.

The SJ details of the HAT(v1.0.0) are mentioned below.

Solder Jumper	Corresponding GPIO	Default State	Purpose	Affect of changing the default state
SJ1	GPIO26	CONNECTED	Cut to disconnect from HAT_PWR_OFF.	Cannot control the power of the HAT.
SJ2	GPIO19	CONNECTED	Cut to disconnect from W_DISABLE.	Cannot disable Wireless communication.
SJ3	GPIO13	CONNECTED	Cut to disconnect DTR pin from GPIO.	Cannot use for sleep mode control.
SJ4	GPIO6	CONNECTED	Cut to disconnect RI pin from GPIO.	Cannot read the Ring indicator.
SJ5	GPIO22	CONNECTED	Cut to disconnect USER BUTTON	Cannot use User Button.
SJ6	GPIO27	CONNECTED	Cut to disconnect USER LED	Cannot use User Led.
SJ7	RXD	NOT CONNECTED	Solder to connect RX of module. Used to communicate over UART.	-
SJ8	TXD	NOT CONNECTED	Solder to connect TX of module. Used to communicate over UART.	-

USB vs UART

With Quectel mini PCIe modules, the Base HAT can be used via USB or UART. Using USB is recommended since the speed slows down via UART compared to the USB. If one still wants to use the UART, the SJ7 and SJ8 needs to be soldered. The Telit module cannot be used via UART with Base HAT. The UART will work with modules where the RX TX are at PCIe pin 11 & 13.

Info
To use the UART follow the steps mentioned in the UART Configuration guide.