Intermediate
30 min

Chart your course with utmost precision using ZED-F9P and PIC18F45K80

The art of pinpoint accuracy

GNSS RTK Click with EasyPIC v7

Published Nov 01, 2023

Click board™

GNSS RTK Click

Development board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18F45K80

Step into a realm of unparalleled precision with our multi-band GNSS module, seamlessly integrated with cutting-edge multi-band Real Time Kinematics (RTK) technology. Unlock centimeter-level accuracy that revolutionizes the way we navigate and map the world.

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Hardware Overview

How does it work?

GNSS RTK Click is based on the ZED-F9P, a multi-band GNSS module with integrated multi-band RTK technology offering centimeter-level accuracy from U-blox. This GNSS receiver can receive and track multiple GNSS constellations. Thanks to the multi-band RF front-end architecture, all four major GNSS constellations (GPS, GLONASS, Galileo, and BeiDou) plus SBAS and QZSS satellites can be received concurrently. Combining GNSS signals from multiple frequency bands (L1/L2/L5) and RTK technology allows the ZED-F9P to achieve centimeter-level accuracy in seconds. Receiving more satellite signals at any given time maximizes the availability of centimeter-level accuracy even in challenging environments such as cities. The ZED-F9P has built-in support for standard RTCM corrections, routed on the additional header, unpopulated by default, and available as an optional standalone RTCM input interface that can not be used as a host interface. It also ensures the security of positioning and navigation information using secure interfaces and advanced jamming and spoofing detection technologies. GNSS RTK Click communicates with MCU using the UART interface at 9600 bps as its default communication protocol with the option for the users to use other interfaces, such as SPI and I2C if they want to configure the module and write the library by themselves. The interface

selection between UART/SPI can be performed by positioning SMD jumpers labeled COMM SEL to an appropriate position. When selecting the SPI communication, with the correct selection of the COMM SEL jumper, it is necessary to set the jumper to DSEL to configure the interface pins as SPI. In the default state, the jumper labeled as DSEL is unpopulated. The receiver also can enter a safe boot mode. If the jumper labeled SFBT is populated and the SAFEBOOT pin is low at Power-Up, the receiver starts in safe boot mode, and GNSS operation is disabled. The USB interface, compatible with the USB version 2.0 FS (Full Speed, 12 Mbit/s), can be used for communication as an alternative to the UART. The USB port can be used as a power supply if you need the Click board™ to be a standalone device. In the case of the main supply failure, the module can use a backup supply voltage from a connected battery. Backup voltage supplies the real-time clock and battery-backed RAM and enables all relevant data to be saved in the backup RAM to allow a hot or warm start later. In addition to these features, it also has several GPIO pins. RDY pin routed to the AN pin of the mikroBUS™ socket is used as a communication indicator when bytes are ready to be transmitted, the RST pin routed on the PWM pin of the mikroBUS™ socket provides the ability to reset the receiver, and the TMP pin, with LED

indicator, routed on the INT pin of the mikroBUS™ socket provides clock pulses with configurable duration and frequency. RTK pin routed on the RST pin of the mikroBUS™ socket, alongside the LED indicator labeled RTK, indicates the RTK positioning status. When the LED blinks, it indicates that a valid stream of RTCM messages is being received, but no RTK fixed mode has been achieved. When the LED is constantly lit, the LED indicates that RTK mode has been achieved. It also has another LED indicator labeled as GDC that indicates the current geofence status of whether the receiver is inside any active areas. For example, this feature can be used to wake up a sleeping host when a defined geofence condition is reached. GNSS RTK Click possesses the SMA antenna connector, and it can be used for connecting the appropriate antenna that Mikroe has in its offer, such as GPS Active External Antenna. This antenna is an excellent choice for all GSM/GPRS applications with a frequency range of 1595.42 ± 25MHz. This Click board™ can be operated only with a 5V 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 RTK 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

default

Architecture

PIC

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

3648

You complete me!

Accessories

GNSS Active External Antenna is a unique multi-band type of antenna coming from u-Blox that is the perfect selection for high precision GNSS applications, which require highly accurate location abilities such as RTK. The ANN-MB-00 is a multi-band (L1, L2/E5b/B2I) active GNSS antenna with a 5m cable and SMA connector. The antenna supports GPS, GLONASS, Galileo, and BeiDou and includes a high-performance multi-band RHCP dual-feed patch antenna element, a built-in high-gain LNA with SAW pre-filtering, and a 5 m antenna cable with SMA connector, and is waterproof.

GNSS RTK Click accessories image

Used MCU Pins

mikroBUS™ mapper

Transmission Ready Indicator
RA2
AN
RTK Positioning Status
RE1
RST
SPI Chip Select
RE0
CS
SPI Clock
RC3
SCK
SPI Data OUT
RC4
MISO
SPI Data IN
RC5
MOSI
NC
NC
3.3V
Ground
GND
GND
Reset
RC0
PWM
Configurable Time Pulses
RB0
INT
UART TX
RC6
TX
UART RX
RC7
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
Power Supply
5V
5V
Ground
GND
GND
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Take a closer look

Schematic

GNSS RTK 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 RTK Click driver.

Key functions:

  • gnssrtk_reset_device - This function resets the device by toggling the RST pin

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

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

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 RTK Click Example.
 *
 * # Description
 * This example reads and processes data from GNSS RTK click.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes driver and starts the module.
 *
 * ## Application Task
 * Reads the received data and parses it.
 *
 * ## Additional Functions
 * - static err_t gnssrtk_process ( void ) - The general process of collecting responses
 *   sent from the module.
 * - static void parser_application ( char *rsp ) - Parsing the response into a more
 *   readable form and printing it on the UART terminal.
 *
 * @author Stefan Nikolic
 *
 */

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

#define PROCESS_COUNTER                         10
#define PROCESS_RX_BUFFER_SIZE                  500
#define PROCESS_PARSER_BUFFER_SIZE              500

#define ELEMENT_BUFFER_NULL                     0

static gnssrtk_t gnssrtk;
static log_t logger;

static char current_parser_buf[ PROCESS_PARSER_BUFFER_SIZE ];

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

static void gnssrtk_process ( void )
{
    int32_t rsp_size;
    uint16_t rsp_cnt = 0;
    
    char uart_rx_buffer[ PROCESS_RX_BUFFER_SIZE ] = { 0 };
    uint16_t check_buf_cnt;
    uint8_t process_cnt = PROCESS_COUNTER;
    
    // Clear parser buffer
    memset( current_parser_buf, 0 , PROCESS_PARSER_BUFFER_SIZE ); 
    
    while( process_cnt != 0 )
{
        rsp_size = gnssrtk_generic_read( &gnssrtk, &uart_rx_buffer, PROCESS_RX_BUFFER_SIZE );

        if ( rsp_size != -1 )
        {  
            // Validation of the received data
            for ( check_buf_cnt = 0; check_buf_cnt < rsp_size; check_buf_cnt++ )
            {
                if ( uart_rx_buffer[ check_buf_cnt ] == 0 ) 
                {
                    uart_rx_buffer[ check_buf_cnt ] = 13;
                }
            } 
            // Storages data in parser buffer
            rsp_cnt += rsp_size;
            if ( rsp_cnt < PROCESS_PARSER_BUFFER_SIZE )
            {
                strncat( current_parser_buf, uart_rx_buffer, rsp_size );
            }
            
            // Clear RX buffer
            memset( uart_rx_buffer, 0, PROCESS_RX_BUFFER_SIZE );
        } 
        else 
        {
            process_cnt--;
            
            // Process delay 
            Delay_ms( 100 );
        }
    }
}

static void parser_application ( char *rsp )
{
    char element_buf[ 200 ] = { 0 };
    
    log_printf( &logger, "\r\n-----------------------\r\n", element_buf ); 
    
    gnssrtk_generic_parser( rsp, GNSSRTK_NMEA_GNGGA, GNSSRTK_GNGGA_LATITUDE, element_buf );
    if ( element_buf[ 0 ] == ELEMENT_BUFFER_NULL )
    {
        log_printf( &logger, "Latitude: No data available!", element_buf );
    }
    else log_printf( &logger, "Latitude:  %s ", element_buf ); 
    
    memset( element_buf, 0, sizeof( element_buf ) );
    
    gnssrtk_generic_parser( rsp, GNSSRTK_NMEA_GNGGA, GNSSRTK_GNGGA_LATITUDE_SIDE, element_buf );
    log_printf( &logger, "%s \r\n", element_buf );
    
    gnssrtk_generic_parser( rsp, GNSSRTK_NMEA_GNGGA, GNSSRTK_GNGGA_LONGITUDE, element_buf );
    if ( element_buf[ 0 ] == ELEMENT_BUFFER_NULL )
    {
        log_printf( &logger, "Longitude: No data available!", element_buf );
    }
    else log_printf( &logger, "Longitude:  %s ", element_buf );
    
    memset( element_buf, 0, sizeof( element_buf ) );
    
    gnssrtk_generic_parser( rsp, GNSSRTK_NMEA_GNGGA, GNSSRTK_GNGGA_LONGITUDE_SIDE, element_buf );
    log_printf( &logger, "%s \r\n", element_buf );
    
    gnssrtk_generic_parser( rsp, GNSSRTK_NMEA_GNGGA, GNSSRTK_GNGGA_ALTITUDE, element_buf );
    if ( element_buf[ 0 ] == ELEMENT_BUFFER_NULL )
    {
        log_printf( &logger, "Alitude: No data available!", element_buf );
    }
    else log_printf( &logger, "Alitude: %s ", element_buf ); 
    
    memset( element_buf, 0, sizeof( element_buf ) );
    
    gnssrtk_generic_parser( rsp, GNSSRTK_NMEA_GNGGA, GNSSRTK_GNGGA_ALTITUDE_UNIT, element_buf );
    log_printf( &logger, "%s \r\n", element_buf );
}

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    gnssrtk_cfg_t gnssrtk_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.

    gnssrtk_cfg_setup( &gnssrtk_cfg );
    GNSSRTK_MAP_MIKROBUS( gnssrtk_cfg, MIKROBUS_1 );
    Delay_ms( 100 );
    err_t init_flag  = gnssrtk_init( &gnssrtk, &gnssrtk_cfg );
    if ( init_flag == UART_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    gnssrtk_default_cfg ( &gnssrtk );
    log_info( &logger, " Application Task " );
    Delay_ms( 100 );
}

void application_task ( void ) {
    gnssrtk_process();
    parser_application( current_parser_buf );
}

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources