Intermediate
30 min

Step into the future of navigation with LG77L and PIC18F4610, where precision reigns supreme

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GNSS 13 Click with EasyPIC v7

Published Sep 02, 2023

Click board™

GNSS 13 Click

Development board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18F4610

Navigate confidently, knowing that each turn and destination is guided by the highest level of precision and reliability

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Hardware Overview

How does it work?

GNSS 13 Click is based on the LG77LICMD, a multi-constellation GNSS module with low power consumption from Quectel Wireless Solutions. It supports concurrent reception of up to three GNSS systems - GPS, GLONASS (or BeiDou), Galileo, and SBAS signals. Compared with single GPS systems, enabling multiple GNSS systems increases the number of visible satellites, reduces the time to a first fix, and improves positioning accuracy, especially in GNSS-hostile environments. By combining EASY™ (Embedded Assist System), an advanced AGNSS feature, with GLP (GNSS Low Power) low power mode, the LG77LICMD achieves high performance, low power consumption, and fully meets industrial standards. The EASY™ technology allows the LG77LICMD to automatically calculate and predict orbits using the ephemeris data (up to 3 days duration) stored in the internal RAM. As a result, the GNSS 13 Click can acquire a fixed position quickly, even at lower signal levels. With the GLP technology, on the other hand, the LG77LICMD can adaptively adjust the ON/OFF time based on the environmental

and motion conditions to achieve a balance between positioning accuracy and power consumption. This Click board™ comes with a configurable host interface that allows communication with MCU using the selected interface. The LG77LICMD can communicate with the MCU using the UART interface with commonly used UART RX and TX pins as its default communication protocol, operating at 115200bps to transmit and exchange data with the host MCU or using the optional I2C interface. The I2C interface is compatible with the Fast-Mode, allowing a maximum bit rate of 400kbit/s. Since the sensor for operation requires a logic voltage level of 1.8V, this Click board™ also features the TLV700, a 1.8V LDO, and an NVT2008 voltage-level translator. The UART and I2C bus lines are routed to the voltage-level translators, allowing this Click board™ to work with 3.3V MCU properly. In addition to all these features, this board has a WUP pin for waking up the module from Backup mode, a general reset feature, as well as several unpopulated headers such as 3DF to indicate

successful positioning, a JAM pin to indicate whether there is any signal jamming, and ANT header with OK and OFF pins for active antenna status detection purposes. GNSS 13 Click possesses the SMA antenna connector on which an appropriate active antenna connects that MIKROE offers for improved range and received signal strength. Also, in the case of the primary supply failure, the module can use a backup supply voltage from a connected battery if you need the Click board™ to be a standalone device. In addition to precise positioning, the GNSS 13 Click also has an accurate timing signal indicated through a red LED indicator marked as PPS. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

GNSS 13 Click hardware overview image

Features overview

Development board

EasyPIC v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyPIC v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of

the EasyPIC v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use various external power sources, including an external 12V power supply, 7-23V AC or 9-32V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B) connector. Communication options such as

USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC v7 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

EasyPIC v7 horizontal image

Microcontroller Overview

MCU Card / MCU

PIC18F4610

Architecture

PIC

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

3968

You complete me!

Accessories

GNSS L1/L5 Active External Antenna (YB0017AA) is an active patch antenna from Quectel that supports GNSS L1/L5 BD B1/B2 GLONASS L1, offering excellent performance with its high gain and efficiency for fleet management, navigation, RTK, and many other tracking applications. The magnetic-mounting antenna, with dimensions of 61.5×56.5×23mm, is designed to work with various ground plane sizes or in free space and is connected to the device by a 3m cable with an SMA male connector.

GNSS 13 Click accessories image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RE1
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Module Wake-Up
RC0
PWM
NC
NC
INT
UART TX
RC6
TX
UART RX
RC7
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Schematic

GNSS 13 Click Schematic schematic

Step by step

Project assembly

EasyPIC v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v7 as your development board.

EasyPIC v7 front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyPIC v7 Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for GNSS 13 Click driver.

Key functions:

  • gnss13_generic_read - This function reads a desired number of data bytes from the module

  • gnss13_parse_gngga - This function parses the GNGGA data from the read response buffer

  • gnss13_clear_ring_buffers - This function clears UART tx and rx ring buffers.

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * @file main.c
 * @brief GNSS 13 Click Example.
 *
 * # Description
 * This example demonstrates the use of GNSS 13 click by reading and displaying
 * the GPS coordinates.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger.
 *
 * ## Application Task
 * Reads the received data, parses the GNGGA info from it, and once it receives
 * the position fix it will start displaying the coordinates on the USB UART.
 *
 * ## Additional Function
 * - static void gnss13_clear_app_buf ( void )
 * - static err_t gnss13_process ( gnss13_t *ctx )
 * - static void gnss13_parser_application ( gnss13_t *ctx, char *rsp )
 * 
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "gnss13.h"
#include "string.h"

#define PROCESS_BUFFER_SIZE 200

static gnss13_t gnss13;
static log_t logger;

static uint8_t app_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;

/**
 * @brief GNSS 13 clearing application buffer.
 * @details This function clears memory of application buffer and reset its length.
 * @return None.
 * @note None.
 */
static void gnss13_clear_app_buf ( void );

/**
 * @brief GNSS 13 data reading function.
 * @details This function reads data from device and concatenates data to application buffer.
 * @param[in] ctx : Click context object.
 * See #gnss13_t object definition for detailed explanation.
 * @return @li @c  0 - Read some data.
 *         @li @c -1 - Nothing is read.
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t gnss13_process ( gnss13_t *ctx );

/**
 * @brief GNSS 13 parser application function.
 * @details This function parses GNSS data and logs it on the USB UART. It clears app and ring buffers
 * after successfully parsing data.
 * @param[in] ctx : Click context object.
 * See #gnss13_t object definition for detailed explanation.
 * @param[in] rsp Response buffer.
 * @return None.
 * @note None.
 */
static void gnss13_parser_application ( gnss13_t *ctx, uint8_t *rsp );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    gnss13_cfg_t gnss13_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );

    // Click initialization.
    gnss13_cfg_setup( &gnss13_cfg );
    GNSS13_MAP_MIKROBUS( gnss13_cfg, MIKROBUS_1 );
    if ( UART_ERROR == gnss13_init( &gnss13, &gnss13_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    if ( GNSS13_OK == gnss13_process( &gnss13 ) )
    {
        if ( PROCESS_BUFFER_SIZE == app_buf_len )
        {
            gnss13_parser_application( &gnss13, app_buf );
        }
    }
}

void main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
}

static void gnss13_clear_app_buf ( void ) 
{
    memset( app_buf, 0, app_buf_len );
    app_buf_len = 0;
}

static err_t gnss13_process ( gnss13_t *ctx ) 
{
    uint8_t rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    int32_t rx_size = 0;
    rx_size = gnss13_generic_read( ctx, rx_buf, PROCESS_BUFFER_SIZE );
    if ( rx_size > 0 ) 
    {
        int32_t buf_cnt = app_buf_len;
        if ( ( ( app_buf_len + rx_size ) > PROCESS_BUFFER_SIZE ) && ( app_buf_len > 0 ) ) 
        {
            buf_cnt = PROCESS_BUFFER_SIZE - ( ( app_buf_len + rx_size ) - PROCESS_BUFFER_SIZE );
            memmove ( app_buf, &app_buf[ PROCESS_BUFFER_SIZE - buf_cnt ], buf_cnt );
        }
        for ( int32_t rx_cnt = 0; rx_cnt < rx_size; rx_cnt++ ) 
        {
            if ( rx_buf[ rx_cnt ] ) 
            {
                app_buf[ buf_cnt++ ] = rx_buf[ rx_cnt ];
                if ( app_buf_len < PROCESS_BUFFER_SIZE )
                {
                    app_buf_len++;
                }
            }
        }
        return GNSS13_OK;
    }
    return GNSS13_ERROR;
}

static void gnss13_parser_application ( gnss13_t *ctx, uint8_t *rsp )
{
    uint8_t element_buf[ 100 ] = { 0 };
    if ( GNSS13_OK == gnss13_parse_gngga( rsp, GNSS13_GNGGA_LATITUDE, element_buf ) )
    {
        static uint8_t wait_for_fix_cnt = 0;
        if ( strlen( element_buf ) > 0 )
        {
            log_printf( &logger, "\r\n Latitude: %.2s degrees, %s minutes \r\n", element_buf, &element_buf[ 2 ] );
            gnss13_parse_gngga( rsp, GNSS13_GNGGA_LONGITUDE, element_buf );
            log_printf( &logger, " Longitude: %.3s degrees, %s minutes \r\n", element_buf, &element_buf[ 3 ] );
            memset( element_buf, 0, sizeof( element_buf ) );
            gnss13_parse_gngga( rsp, GNSS13_GNGGA_ALTITUDE, element_buf );
            log_printf( &logger, " Altitude: %s m \r\n", element_buf );
            wait_for_fix_cnt = 0;
        }
        else
        {
            if ( wait_for_fix_cnt % 5 == 0 )
            {
                log_printf( &logger, " Waiting for the position fix...\r\n\n" );
                wait_for_fix_cnt = 0;
            }
            wait_for_fix_cnt++;
        }
        gnss13_clear_ring_buffers( ctx );
        gnss13_clear_app_buf( );
        Delay_ms ( 500 );
    }
}

// ------------------------------------------------------------------------ END

Additional Support

Resources