Beginner
10 min

Measure, analyze, and optimize radio frequency power with precision using AD8318 and PIC18F47J53

RF Meter: Your gateway to signal strength mastery

RF Meter Click with PIC clicker

Published Oct 18, 2023

Click board™

RF Meter Click

Development board

PIC clicker

Compiler

NECTO Studio

MCU

PIC18F47J53

Keep control of your wireless environment with RF meters, putting the power to measure and manage radio frequency signals right in your hands

A

A

Hardware Overview

How does it work?

RF Meter Click is based on the AD8318, a logarithmic detector/controller from Analog Devices. It is a demodulating logarithmic amplifier capable of accurately converting an RF input signal to a corresponding decibel-scaled output voltage. It employs the progressive compression technique over a cascaded amplifier chain, with each stage equipped with a detector cell. The AD8318 can be used in measurement or controller mode of operation. It maintains accurate log conformance for signals of 1MHz to 6GHz and provides operation up to 8GHz. The input range is typically 60dB with an error of less than ±1dB and a 10ns response time that enables RF burst

detection beyond 45MHz. In addition, the AD8318 comes with an integrated temperature sensor with independent output, which can be used for temperature compensation. The voltage output of the AD8318 goes to the MCP3201, a successive approximation 12-bit analog-to-digital converter with an onboard sample and hold circuitry from Microchip. This ADC provides a single pseudo-differential output, with sample rates of up to 100ksps. To provide correct values, this Click board™ uses an AP7331 LDO linear regulator to provide referent voltage to the MCP3201. The RF Meter uses a 3-wire SPI serial interface of the MCP3201 to communicate to the host MCU

over the mikroBUS™ socket. The RF Meter can use either an SPI mode 0 or an SPI mode 1, depending on the needs. The readings of the independent temperature sensor of the AD8318 can be read over the OUT pin mikroBUS™ socket, giving analog values. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the LOGIC LEVEL 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.

RF Meter Click hardware overview image

Features overview

Development board

PIC Clicker is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It has an onboard 8-bit PIC microcontroller, the PIC18F47J53 from Microchip, a USB connector, LED indicators, buttons, a mikroProg connector, and a header for interfacing with external electronics. Thanks to its compact design with clear and easy-recognizable silkscreen markings, it provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances. Each part of the PIC Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the PIC Clicker programming method, using USB HID mikroBootloader, or through an external mikroProg connector for PIC, dsPIC, or PIC32 programmer, the Clicker board also includes a clean and regulated power supply module for the development kit. The USB Mini-B connection can provide up to 500mA of current, which is more than enough to operate all onboard and additional

modules. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several buttons and LED indicators. PIC Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

PIC clicker double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

44

RAM (Bytes)

3800

Used MCU Pins

mikroBUS™ mapper

Temperature Output
RA2
AN
NC
NC
RST
SPI Chip Select
RB3
CS
SPI Clock
RB4
SCK
SPI Data OUT
RB5
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

RF Meter Click Schematic schematic

Step by step

Project assembly

PIC clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the PIC clicker as your development board.

PIC clicker front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Mini B Connector Clicker Access - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto_MCU_Select_PICPLC16 hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for RF Meter Click driver.

Key functions:

  • rfmeter_get_signal_strenght - Function is used to calculate radio frequency signal strenght in a vicinity

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 
 * \brief Rfmeter Click example
 * 
 * # Description
 * Demo app measures and displays signal strenght by using RF Meter click board.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initalizes SPI, LOG and click drivers.
 * 
 * ## Application Task  
 * This is an example that shows the capabilities of the RF Meter click by 
 * measuring radio frequency signal strenght.
 * 
 * \author Jovan Stajkovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rfmeter.h"

// ------------------------------------------------------------------ VARIABLES

static rfmeter_t rfmeter;
static log_t logger;
static float signal;

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


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

void application_init ( void )
{
    log_cfg_t log_cfg;
    rfmeter_cfg_t cfg;

    /** 
     * 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.

    rfmeter_cfg_setup( &cfg );
    RFMETER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rfmeter_init( &rfmeter, &cfg );
    log_printf( &logger, "----------------------- \r\n" );
    log_printf( &logger, "    RF Meter Click      \r\n" );
    log_printf( &logger, "----------------------- \r\n" );
}

void application_task ( void )
{
    signal = rfmeter_get_signal_strenght( &rfmeter, RFMETER_DEF_SLOPE, RFMETER_DEF_INTERCEPT );
    
    log_printf( &logger, "Signal strenght: %.2f dBm \r\n", signal );
    
    Delay_ms( 1000 );
    log_printf( &logger, "-----------------------\r\n" );
}

void main ( void )
{
    application_init( );

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


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

Additional Support

Resources