30 min

Transform time into digital insights with TDC7200 and STM32F302VC

Counting moments, capturing dreams

TDC Click with UNI-DS v8

Published May 27, 2023

Click board™

TDC Click

Development board



NECTO Studio



Achieve unparalleled accuracy in time-of-flight and flow meter applications, particularly in zero and low flow measurements



Hardware Overview

How does it work?

TDC Click is based on the TDC7200, a time-to-digital converter for time-of-flight (ToF) applications for LIDAR and ultrasonic from Texas Instruments. This stopwatch IC measures the time between a single event known as time-of-flight (an edge on START signal) and multiple subsequent events (an edge on STOP signal), which are brought to the onboard SMA connectors marked as START and STOP. The user also can pair this Click board™ with some external board that contains the TDC1000 (ultrasonic analog front-end) and become a part of a complete ultrasonic sensing solution for measurements such as water, gas, and heat flow meter. The TDC7200 has an internal self-calibrated time base compensating for drift over time and temperature used to measure time accurately in the order of picoseconds. When placed in the Autonomous Multi-Cycle

Averaging mode of operation, the TDC7200 can be optimized for low system power consumption. The host can sleep to save power, and the TDC can wake it up upon completion of the measurement sequence. The TDC7200 also has an external reference clock to calibrate the internal time base accurately. All digital circuits inside the device also use this reference clock; thus, the clock must be available and stable when the device is enabled. For this reason, there is the possibility of selecting an external clock connected to a miniature coaxial N.FL series connector or an internal one by an onboard 8MHz crystal that can be activated via an OEN pin routed on the AN pin of the mikroBUS™ socket. Selection can be performed by onboard SMD jumper labeled as CLK SEL to an appropriate position marked as EXT and INT.

The TDC7200 communicates with MCU using the standard SPI serial interface with a maximum frequency of 20MHz. In addition, it also uses several additional GPIO pins, such as the EN pin routed on the RST pin of the mikroBUS™ socket used as a reset to all digital circuits in the TDC7200, the TRG pin routed on the PWM pin of the mikroBUS™ socket as a start measurement trigger and INT pin which determine TDC measurement completion. This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ 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

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



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Onboard Crystal Enable
TDC Enable
SPI Chip Select
SPI Clock
Power Supply
Start Measurement Trigger

Take a closer look


TDC 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
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN Access 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 TDC Click driver.

Key functions:

  • tdc_cfg_setup - Config Object Initialization function.
  • tdc_init - Initialization function.
  • tdc_default_cfg - Click Default Configuration function.

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 Tdc Click example
 * # Description
 * This library contains an API for the TDC Click driver.
 * This demo application shows the use of a TDC Click board™.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initialization of SPI module and log UART.
 * After driver initialization, the app set default settings and 
 * the configures the measurement ( set the pulse to 100 us ).
 * ## Application Task
 * This is an example that shows the use of a TDC Click board™.
 * In this example, after the START signal, the app sends 3 STOP signals per 100 microseconds.
 * The application reads and displays the value of Time, Clock count and 
 * Time-of-Flight values of three performed measurements.
 * Results are being sent to the Usart Terminal where you can track their changes.
 * @author Nenad Filipovic

#include "board.h"
#include "log.h"
#include "tdc.h"

static tdc_t tdc;
static tdc_t tdc_pulse;
static log_t logger;
static uint16_t pulse_us;
static uint8_t count_stop;
static uint8_t num_stops;

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    tdc_cfg_t tdc_cfg;  /**< Click config object. */
    tdc_cfg_t tdc_cfg1;
    static uint8_t cal_periods;
    static uint8_t avg_cycles;
    static uint8_t sel_mode;

     * 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.

    tdc_cfg_setup( &tdc_cfg );
    TDC_MAP_MIKROBUS( tdc_cfg, MIKROBUS_1 );
    tdc_cfg_setup( &tdc_cfg1 );
    TDC_MAP_MIKROBUS( tdc_cfg1, MIKROBUS_2 );
    err_t init_flag  = tdc_init( &tdc, &tdc_cfg );
    init_flag  |= tdc_init( &tdc_pulse,  &tdc_cfg1 );
    if ( SPI_MASTER_ERROR == init_flag ) 
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    tdc_default_cfg ( &tdc );
    log_info( &logger, " Application Task " );
    Delay_ms( 100 );
    cal_periods = 10;
    avg_cycles = 1;
    num_stops = 3;
    sel_mode = 1;
    pulse_us = 100;
    count_stop = 1;
    tdc_setup_measurement( &tdc, cal_periods, avg_cycles, num_stops, sel_mode );
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms( 100 );

void application_task ( void ) 
    static uint32_t p_time[ 5 ];
    static uint32_t p_clock_count[ 5 ];
    static uint32_t p_tof[ 5 ];
    tdc_start_measurement( &tdc );

    while ( tdc_get_trg( &tdc ) == 0 );
    tdc_gen_pulse( &tdc_pulse, pulse_us, num_stops );
    while ( tdc_get_interrupt( &tdc ) == 1 );
    tdc_get_measurement( &tdc, TDC_MCU_CLOCK_MODE_168_MHZ, count_stop, p_time, p_clock_count, p_tof );
    log_printf( &logger, " Time[ 0 ]        = %lu\r\n", p_time[ 0 ] ); 
    log_printf( &logger, " Time[ 1 ]        = %lu\r\n", p_time[ 1 ] ); 
    log_printf( &logger, " Time[ 2 ]        = %lu\r\n", p_time[ 2 ] );
    log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );
    log_printf( &logger, " Clock count[ 0 ] = %lu\r\n", p_clock_count[ 0 ] );
    log_printf( &logger, " Clock count[ 1 ] = %lu\r\n", p_clock_count[ 1 ] );
    log_printf( &logger, " Clock count[ 2 ] = %lu\r\n", p_clock_count[ 2 ] );
    log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );

    log_printf( &logger, " TOF[ 0 ]         = %u us\r\n", p_tof[ 0 ] ); 
    log_printf( &logger, " TOF[ 1 ]         = %u us\r\n", p_tof[ 1 ] );  
    log_printf( &logger, " TOF[ 2 ]         = %u us\r\n", p_tof[ 2 ] );    
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms( 1000 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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

Additional Support