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30 min

Create a a reliable platform for encoding, decoding, and transmitting telephonic signals with CMX865A and PIC32MZ2048EFM100

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DTMF Click with Curiosity PIC32 MZ EF

Published Mar 11, 2024

Click board™

DTMF Click

Dev. board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

Enhance your projects with crystal-clear voice and data communications, easily managed through advanced DTMF signal processing technology

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Hardware Overview

How does it work?

DTMF Click is based on the CMX865A, a high-performance DTMF Codec/FSK Combo multi-standard modem from CML Micro. This Click board™ stands out for its integration of both an industrial standard DTMF encoder/decoder and a versatile FSK modem, catering to a variety of telephone connectivity and interconnect applications. The CMX865A's ability to handle basic call setups and progress functionalities, coupled with its capacity for data signaling, makes it suitable for remote control, status notification, and data acquisition across numerous fields. As mentioned, the CMX865A combines a high-quality DTMF decoder known for its resistance to voice falsing and a multifaceted FSK modem that supports standards like V.23, V.21, Bell 103, and Bell 202. Users benefit from its dual operational

modes, which are programmable for transmission and reception, allowing for the transmission of programmed signals, simple melodies, or modem tones. Its applicability extends to security systems that rely on DTMF for access control, automated response services for customer interaction, and IoT devices requiring remote control over telephony networks. Additionally, its on-chip line driver, hybrid, and receiver circuits, complemented by external components and a P1200 transformer, offer a complete, fully isolated line interface solution. Data and control exchanges between the CMX865A and the host MCU are made through a C-BUS interface, compatible with a standard 4-wire SPI interface of the mikroBUS™ socket. The board also uses the mikroBUS™ socket's RDN pin and a red RING LED to indicate ringing signals and the

IRQ pin for interrupt requests related to call states like busy, dialing, and connected statuses. The HSW pin, alongside a blue HOOK LED, also serves as a hookswitch to manage the line interface's connectivity status (0-OFF, 1-ON). An additional feature of the CMX865A is the Powersave mode, which conserves energy by deactivating all circuits except the essential C-BUS (SPI) interface. 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.

DTMF Click hardware overview image

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.

Curiosity PIC32MZ EF double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

Ringing Indicator
RPB4
AN
Board Hook Switch
RA9
RST
SPI Chip Select
RPD4
CS
SPI Clock
RPD1
SCK
SPI Data OUT
RPD14
MISO
SPI Data IN
RPD3
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
RF13
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

DTMF Click Schematic schematic

Step by step

Project assembly

Curiosity PIC32MZ EF front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.

Curiosity PIC32MZ EF front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Board mapper by product7 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
Curiosity PIC32 MZ EF MCU Step 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

Software Support

Library Description

This library contains API for DTMF Click driver.

Key functions:

  • dtmf_handshake_init - This function performs a handshake init which resets the device settings to default

  • dtmf_dial - This function dials the selected number by alternating between DTMF and No-tone

  • dtmf_send_message - This function sends an array of bytes via V.23 FSK 1200bps modem in start-stop 8.1 mode

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * @file main.c
 * @brief DTMF Click example
 *
 * # Description
 * This example demonstrates the use of DTMF Click board by showing
 * the communication between the two Click boards connected to PBX system.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger, and displays the selected application mode.
 *
 * ## Application Task
 * Dialing application mode:
 * - Resets the device settings and dials the selected number. If a call is answered
 * it starts sending desired messages every couple of seconds with constantly checking
 * if a call is still in progress or it's terminated from the other side.
 * Answering application mode:
 * - Resets the device settings and waits for an incoming call indication, answers the call,
 * and waits for a desired number of messages. The call is terminated after all messages
 * are received successfully.
 *
 * @note
 * We have used a Yeastar S20 VoIP PBX system for the test, where the Click boards are
 * connected to ports 1 and 2 configured as FXS extension with numbers 1000 and 1001 (dialer).
 * 
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "dtmf.h"

// Demo aplication selection macros
#define APP_DIALING                 0
#define APP_ANSWERING               1
#define DEMO_APP                    APP_DIALING

// Dialing application settings - a dial number and text to send (must end with CRLF - \r\n)
#define DIAL_NUMBER                 "1000"
#define TEXT_TO_SEND                "MIKROE - DTMF Click\r\n"

// Answering application settings - a number of successfully received messages before call termination
#define NUM_MESSAGES                5u

static dtmf_t dtmf;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    dtmf_cfg_t dtmf_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.
    dtmf_cfg_setup( &dtmf_cfg );
    DTMF_MAP_MIKROBUS( dtmf_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == dtmf_init( &dtmf, &dtmf_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

#if ( DEMO_APP == APP_DIALING )
    log_printf( &logger, " Application Mode: Dialing\r\n" );
#elif ( DEMO_APP == APP_ANSWERING )
    log_printf( &logger, " Application Mode: Answering\r\n" );
#else
    #error "Selected application mode is not supported!"
#endif
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    uint8_t state = DTMF_STATE_IDLE;
    uint32_t time_cnt = 0;
    uint8_t msg_cnt = 0;

    dtmf_handshake_init ( &dtmf );

#if ( DEMO_APP == APP_DIALING )
    log_printf( &logger, "\r\n Hook OFF\r\n" );
    dtmf_hook_off ( &dtmf );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    log_printf( &logger, " Dial: %s\r\n", ( char * ) DIAL_NUMBER );
    dtmf_dial ( &dtmf, DIAL_NUMBER );
    dtmf.rx_mode &= DTMF_RX_LEVEL_MASK; // No change in rx level setting
    dtmf.rx_mode |= ( DTMF_RX_MODE_DTMF_TONES | DTMF_RX_TONE_DETECT_CALL_PROG );
    dtmf_set_receive_mode ( &dtmf, dtmf.rx_mode );
    for ( ; ; )
    {
        Delay_ms ( 1 );
        if ( !dtmf_get_irq_pin ( &dtmf ) )
        {
            time_cnt = 0;
            state = DTMF_STATE_IRQ_SET;
        }
        if ( ( DTMF_STATE_IRQ_SET == state ) && !dtmf_call_progress ( &dtmf ) )
        {
            if ( time_cnt < DTMF_TIMING_BUSY )
            {
                log_printf( &logger, " Busy\r\n" );
                break;
            }
            else if ( time_cnt < DTMF_TIMING_DISCONNECTED )
            {
                log_printf( &logger, " Disconnected\r\n" );
                break;
            }
            else if ( time_cnt < DTMF_TIMING_RINGING )
            {
                log_printf( &logger, " Ringing\r\n" );
                state = DTMF_STATE_RINGING;
            }
        }
        if ( ( DTMF_STATE_RINGING == state ) && ( time_cnt > DTMF_TIMING_CALL_PROGRESS ) )
        {
            log_printf( &logger, " Call in progress\r\n" );
            state = DTMF_STATE_CALL_IN_PROGRESS;
            time_cnt = 0;
        }
        if ( ( DTMF_STATE_CALL_IN_PROGRESS == state ) && !( time_cnt % DTMF_TIMING_SEND_MESSAGE ) )
        {
            log_printf( &logger, " Send message %u\r\n", ( uint16_t ) msg_cnt++ );
            dtmf_send_message ( &dtmf, TEXT_TO_SEND, strlen ( TEXT_TO_SEND ) );
        }
        if ( time_cnt++ > DTMF_TIMEOUT_CALL_PROGRESS )
        {
            log_printf( &logger, " Timeout\r\n" );
            break;
        }
    }
    log_printf( &logger, " Hook ON\r\n" );
    dtmf_hook_on ( &dtmf );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#elif ( DEMO_APP == APP_ANSWERING )
    uint8_t rx_data = 0;
    uint8_t msg_end_buff[ 2 ] = { 0 };

    log_printf( &logger, "\r\n Waiting for a call...\r\n" );

    while ( dtmf_get_rdn_pin ( &dtmf ) );

    Delay_ms ( 1000 );
    log_printf( &logger, " Hook OFF\r\n" );
    dtmf_hook_off ( &dtmf );
    Delay_ms ( 1000 );
    log_printf( &logger, " Waiting for %u messages...\r\n", ( uint16_t ) NUM_MESSAGES );
    dtmf.rx_mode &= DTMF_RX_LEVEL_MASK; // No change in rx level setting
    dtmf.rx_mode |= ( DTMF_RX_MODE_V23_FSK_1200 | DTMF_RX_USART_START_STOP | DTMF_RX_DATA_PARITY_8_NO_PAR );
    dtmf_set_receive_mode ( &dtmf, dtmf.rx_mode );

    for ( ; ; )
    {
        Delay_ms ( 1 );
        if ( !dtmf_get_irq_pin ( &dtmf ) )
        {
            if ( DTMF_STATE_IDLE != state )
            {
                log_printf( &logger, "\r\n Disconnected\r\n" );
                break;
            }
            log_printf( &logger, " Message %u: ", ( uint16_t ) msg_cnt );
            state = DTMF_STATE_IRQ_SET;
            time_cnt = 0;
        }
        if ( ( DTMF_STATE_IRQ_SET == state ) && !( time_cnt % DTMF_TIMING_RX_READY ) )
        {
            if ( dtmf_unscram_1s_det ( &dtmf ) && dtmf_rx_ready ( &dtmf ) )
            {
                dtmf_receive_data ( &dtmf, &rx_data );
                log_printf( &logger, "%c", ( uint16_t ) rx_data );
                if ( '\r' == rx_data )
                {
                    msg_end_buff[ 0 ] = rx_data;
                }
                else if ( '\n' == rx_data )
                {
                    msg_end_buff[ 1 ] = rx_data;
                }
                else
                {
                    msg_end_buff[ 0 ] = 0;
                    msg_end_buff[ 1 ] = 0;
                }
            }
            if ( ( '\r' == msg_end_buff[ 0 ] ) && ( '\n' == msg_end_buff[ 1 ] ) )
            {
                msg_end_buff[ 0 ] = 0;
                msg_end_buff[ 1 ] = 0;
                state = DTMF_STATE_IDLE;
                if ( NUM_MESSAGES == ++msg_cnt )
                {
                    Delay_ms ( 100 );
                    log_printf( &logger, " Terminate call\r\n" );
                    Delay_ms ( 100 );
                    break;
                }
            }
        }
        if ( time_cnt++ > DTMF_TIMING_WAIT_FOR_MESSAGE )
        {
            log_printf( &logger, "\r\n Timeout\r\n" );
            break;
        }
    }
    log_printf( &logger, " Hook ON\r\n" );
    dtmf_hook_on ( &dtmf );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#endif
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

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

Additional Support

Resources

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