Craft seamless signals for mobile communication systems with HT9200A and PIC32MZ2048EFM100
Behind the dial: Uncover the brilliance of the DTMF decoder
Published Oct 22, 2023
Click board™
DTMF Generator Click
Dev Board
Curiosity PIC32 MZ EF
Compiler
NECTO Studio
MCU
PIC32MZ2048EFM100
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.
Features overview
Development board
Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand
functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,
which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC32
MCU Memory (KB)
2048
Silicon Vendor
Microchip
Pin count
100
RAM (Bytes)
524288
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for DTMF Generator Click driver.
Key functions:
dtmfgenerator_set_dat- Set DATA ( RST ) pin state functiondtmfgenerator_power_on- Power ON functiondtmfgenerator_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
