Intermediate
30 min
0

Craft seamless signals for mobile communication systems with HT9200A and PIC18F96J65

Behind the dial: Uncover the brilliance of the DTMF decoder

DTMF Generator Click with UNI-DS v8

Published Oct 22, 2023

Click board™

DTMF Generator Click

Development board

UNI-DS v8

Compiler

NECTO Studio

MCU

PIC18F96J65

Journey into the world of DTMF signal generation, where we uncover the magic that results in the creation of Dual-Tone Multi-Frequency signals vital for mobile communication systems

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Hardware Overview

How does it work?

DTMF Generator Click is based on the HT9200A, a dual-tone multi-frequency decoder from Holtek Semiconductor for mobile communication systems. The HT9200A is an SMD tone generator IC designed for MCU interfaces. It can be instructed by an MCU to generate 16 dual tones and eight single tones from the DTMF pin, and it provides a Serial Mode. The system oscillator of HT9200A consists of an inverter, a bias resistor, and the required load capacitor on a chip. The oscillator function is implemented with a standard 3.579545MHz crystal connected to the X1 and X2 pins of the HT9200A. The operation of the HT9200A is based on GPIO signals fed from the mikroBUS™ to the decoder, DAT, and CLK. There is a connection between the digital codes and the tone output frequency based on the selected desired output frequency. The HT9200A employs a

data input, a 5-bit code, and a synchronous clock to transmit a DTMF signal. Every digit of a transferred number is selected by a series of combinations that consist of 5-bit data. The HT9200A will latch data on the falling edge of the CLK pin and display the output data on its output DTMF pin. Then, via a volume adjustment potentiometer, such a signal is sent to an audio amplifier, the LM386 from Texas Instruments, which represents a mono low-voltage amplifier that can be used in various applications. After the audio amplifier, the desired sound can be detected on the on-board speaker. DTMF Generator Click communicates with MCU using three GPIO pins routed on the CS, RST, and PWM pins of the mikroBUS™ socket labeled CE, DAT, and CLK. CE pin represents the Chip Enable function used to wake up the HT9200A, while DAT

and CLK pins represent data input and synchronous clock input. It also possesses an adjustable potentiometer labeled as VOLUME that adjusts the volume of that signal. It also has a 3.5mm jack output connector that allows the user to use the output DTMF signal in their projects in their way while the signal volume can still be adjusted on the VOLUME potentiometer located on the DTMF Generator Click. 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.

DTMF Generator Click top side image
DTMF Generator Click bottom side image

Features overview

Development board

UNI-DS v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different STM32, Kinetis, TIVA, CEC, MSP, PIC, dsPIC, PIC32, and AVR MCUs regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, UNI-DS v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the UNI-DS v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector. Communication options such as USB-UART, USB

HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. UNI-DS v8 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.

UNI-DS v8 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

PIC

MCU Memory (KB)

96

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

3808

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Data Input
PG6
RST
Chip Enable
PG4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Data Synchronous Clock Input
PC1
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

DTMF Generator Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI-DS v8 as your development board.

Fusion for PIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
v8 SiBRAIN 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 image step 7 hardware assembly
Necto image step 8 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 DTMF Generator Click driver.

Key functions:

  • dtmfgenerator_set_dat - Set DATA ( RST ) pin state function

  • dtmfgenerator_power_on - Power ON function

  • dtmfgenerator_transmit_out_tone - The function transmit duration time of the desired tone

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 DTMF Generator Click Example.
 *
 * # Description
 * This is an example which demonstrates the use of DTMF Generator Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization driver enables - GPIO,
 * run the power-on sequence, also write log.
 *
 * ## Application Task
 * DTMF Generator click board DTMF generator transmits the signal 
 * for generating tone for digits :
 * "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
 * "A", "B", "C", "D", "*" and "#".
 * All data logs write on USB uart changes.
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "dtmfgenerator.h"

static dtmfgenerator_t dtmfgenerator;   /**< DTMF Generator Click driver object. */
static log_t logger;    /**< Logger object. */

static uint16_t signal_duration = 500;

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    dtmfgenerator_cfg_t dtmfgenerator_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.
    dtmfgenerator_cfg_setup( &dtmfgenerator_cfg );
    DTMFGENERATOR_MAP_MIKROBUS( dtmfgenerator_cfg, MIKROBUS_1 );
    if ( DIGITAL_OUT_UNSUPPORTED_PIN == dtmfgenerator_init( &dtmfgenerator, &dtmfgenerator_cfg ) ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    log_printf( &logger, " Powering on device \r\n" );
    log_printf( &logger, "--------------------\r\n" );
    dtmfgenerator_power_on( &dtmfgenerator );
    Delay_ms( 1000 );
    log_info( &logger, " Application Task " );
}

void application_task ( void ) {
    log_printf( &logger, " TONE      '0' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_0, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '1' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_1, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '2' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_2, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '3' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_3, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '4' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_4, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '5' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_5, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '6' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_6, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '7' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_7, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '8' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_8, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '9' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_9, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      'A' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_A, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      'B' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_B, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      'C' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_C, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      'D' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_D, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '*' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_ASTERISK, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
    
    log_printf( &logger, " TONE      '#' \r\n");
    log_printf( &logger, "---------------\r\n" );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_HASH, signal_duration );
    dtmfgenerator_transmit_out_tone( &dtmfgenerator, DTMFGENERATOR_OUT_TONE_STOP, signal_duration );
 }

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources