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.
Features overview
Development board
Clicker 4 for STM32F4 is a compact development board designed as a complete solution that you can use to quickly build your own gadgets with unique functionalities. Featuring an STM32F407VGT6 MCU, four mikroBUS™ sockets for Click boards™ connectivity, power management, and more, it represents a perfect solution for the rapid development of many different types of applications. At its core is an STM32F407VGT6 MCU, a powerful microcontroller by STMicroelectronics based on the high-performance
Arm® Cortex®-M4 32-bit processor core operating at up to 168 MHz frequency. It provides sufficient processing power for the most demanding tasks, allowing Clicker 4 to adapt to any specific application requirements. Besides two 1x20 pin headers, four improved mikroBUS™ sockets represent the most distinctive connectivity feature, allowing access to a huge base of Click boards™, growing on a daily basis. Each section of Clicker 4 is clearly marked, offering an intuitive and clean interface. This makes working with the
development board much simpler and, thus, faster. The usability of Clicker 4 doesn’t end with its ability to accelerate the prototyping and application development stages: it is designed as a complete solution that can be implemented directly into any project, with no additional hardware modifications required. Four mounting holes [4.2mm/0.165”] at all four corners allow simple installation by using mounting screws.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
10
Silicon Vendor
STMicroelectronics
Pin count
100
RAM (Bytes)
100
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project 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.
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™.
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.
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 defaultdtmf_dial
- This function dials the selected number by alternating between DTMF and No-tonedtmf_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
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 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 ( 4000 );
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 ( 4000 );
#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 ( 4000 );
#endif
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END