4G LTE 2 Click – Voice (for North America)

How does it work?

4G LTE 2 Click – Voice (for North America) is based on the LARA-R6401, a multi-band and multi-mode module from LARA-R6 series from u-blox, supporting LTE Cat 1 FDD and LTE Cat 1 TDD radio access technology (18 LTE bands), with 3G UMTS/HSPA and 2G GSM/GPRS/EGPRS fallback providing the ideal solution for uncompromised connectivity for the North American market. This Click board™ represents a data and voice solution with global coverage and all relevant MNO certifications, offering great flexibility and the support of voice/audio applications. Versatile interfaces and features make the LARA-R6401 ideally suited for a wide range of applications that require medium data speed, seamless connectivity, superior coverage, low latency, and streaming data such as asset tracking, telematics, remote monitoring, point-of-sale terminals, and more.

The LARA-R6401 module provides Voice over LTE (VoLTE) and Circuit-Switched-Fall-Back (CSFB) from LTE to 3G or 2G radio bearer for audio services users can access via an onboard 3.5mm audio jack. This audio interface is configurable through the AT commands to transfer digital audio data to/from an external device as an onboard audio codec.

This module requires a power supply of 3.8V. Therefore, the Click board™ incorporates an integrated buck (step-down DC-DC) converter, labeled as TPS7A7002 by Texas Instruments, which provides a stable 3.8V power supply, capable of mitigating voltage drops at the input when a high current peak appears (typically at the StartUp of the device). The module Ignition (Power-On) pin, labeled as PWR and routed to the RST pin on the mikroBUS™ socket, offers a switch operation to turn ON/OFF power delivery to the LARA-R6401.

The LARA-R6401 communicates with MCU using the UART interface with commonly used UART RX and TX pins with the hardware flow control pins UART CTS, RTS, RI (Clear to Send, Ready to Send, and Ring Indicator). It operates at 115200 bps by default configuration to transmit and exchange data with the host MCU through AT commands that u-blox provides. Besides the UART interface, the LARA-R6401 also allows the I2C interface to act as an I2C host, which can communicate with I2C local devices following the I2C bus specifications. This Click board™ is also equipped with a USB type C connector, available for diagnostic purposes only. The module is a USB device and can be connected to any USB host with compatible drivers.

Among its used pins, this Click board™ also possesses two additional LED indicators: the yellow LED labeled as STATUS, routed both to the mikroBUS™ AN pin (STS) and the LED, used to indicate the status of the network connection visually, and a red LED labeled as TX used to tell the transmitting status of the module.

The LTE cellular networks use spatial multiplexing antenna technology, allowing more than one antenna to be used for better reception of the specific frequency channel. For that reason, besides the primary TX/RX antenna, this Click board™ uses a secondary diversity RX antenna, which allows better signal reception. Alongside those SMA connectors, the 4G LTE 2 Click also has a Nano-SIM card slot that provides multiple connections and interface options alongside several test points labeled from TP1 to TP3, enabling easy reboot and testing of the module.

This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

Specifications

Pinout diagram

This table shows how the pinout on 4G LTE 2 Click – Voice (for North America) corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Module Status	STS	1	AN	PWM	16	RI	UART RI
Power-ON	PWR	2	RST	INT	15	CTS	UART CTS
UART RTS	RTS	3	CS	RX	14	TX	UART TX
	NC	4	SCK	TX	13	RX	UART RX
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

4G LTE 2 Click – Voice (for North America) electrical specifications

Software Support

We provide a library for the 4G LTE 2 Voice-NA Click as well as a demo application (example), developed using MIKROE compilers. The demo can run on all the main MIKROE development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for 4G LTE 2 Voice-NA Click driver.

Key functions

• c4glte2voicena_set_power_state This function sets a desired power state by toggling PWR pin with a specific time for high state.

• c4glte2voicena_set_sim_apn This function sets APN for sim card.

• c4glte2voicena_send_sms_text This function sends text message to a phone number.

Example Description

Application example shows device capability of connecting to the network and sending SMS or TCP/UDP messages using standard “AT” commands.

void application_task ( void ) 
 { 
     switch ( example_state ) 
     { 
         case C4GLTE2VOICENA_CONFIGURE_FOR_NETWORK: 
         { 
             if ( C4GLTE2VOICENA_OK == c4glte2voicena_cfg_for_network( ) ) 
             { 
                 example_state = C4GLTE2VOICENA_WAIT_FOR_CONNECTION; 
             } 
             break; 
         } 
         case C4GLTE2VOICENA_WAIT_FOR_CONNECTION: 
         { 
             if ( C4GLTE2VOICENA_OK == c4glte2voicena_check_connection( ) ) 
             { 
                 example_state = C4GLTE2VOICENA_CONFIGURE_FOR_EXAMPLE; 
             } 
             break; 
         } 
         case C4GLTE2VOICENA_CONFIGURE_FOR_EXAMPLE: 
         { 
             if ( C4GLTE2VOICENA_OK == c4glte2voicena_cfg_for_example( ) ) 
             { 
                 example_state = C4GLTE2VOICENA_EXAMPLE; 
             } 
             break; 
         } 
         case C4GLTE2VOICENA_EXAMPLE: 
         { 
             c4glte2voicena_example( ); 
             break; 
         } 
         default: 
         { 
             log_error( &logger, " Example state." ); 
             break; 
         } 
     } 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.4GLTE2VoiceNA

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MIKROE Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.