Intermediate
30 min

Track time with laser precision using AS6500 and PIC18F57Q43

Sync up - time waits for none

TDC 2 Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

TDC 2 Click

Dev. board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Unleash the boundless possibilities of this high-performance time-to-digital converter today

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Hardware Overview

How does it work?

TDC 2 Click is based on the AS6500, a high-resolution time-to-digital converter from ScioSense, featuring CMOS inputs, high measurement performance, and high data throughput. The AS6500 can measure time intervals as low as 5ns with 10ps resolution on all four STOP channels at a sampling rate of up to 1.5Ms/s. It is characterized by high configuration flexibility, a wide measurement range from 0 to 16s, and simple data post-processing thanks to calibrated results. It calculates calibrated stop measurements referenced to the applied reference clock. This Click board™ is ideal for optical applications, including general-purpose laser distance measurement in 1D, 2D, and 3D, speed control, object recognition, time-of-flight spectroscopy, and many more. The positive edges of the stop signals, applied on the STOP terminals (1-4), are measured versus the preceding reference clock edge. The reference clock can be brought externally via the CLR

pin on the middle header terminal or from the onboard 8MHz quartz oscillator. This feature is selectable through software – register-setting. The reference clock represents the framework for all time measurements and serves as a universal time base. The TDC measures the clock pulses continuously as a time reference point for STOP pulses and an internal reference period. The measurement of the STOP events always refers to the preceding reference clock. The reference clock is counted continuously, and the actual count is assigned as a reference index to a STOP pulse. TDC 2 Click communicates with the host MCU through a standard SPI interface to read data and configure the frontend, supporting high clock speed up to 50MHz and the most common SPI mode, SPI Mode 1. SPI pins also use an interrupt pin that indicates to the host MCU that data are available and ready for processing. The AS6500 uses several more signals available on the

mikroBUS™ socket for successful time measurements. With the RIR pin, the internal counter for the reference index is set back to zero, simplifying the overview of the reference index in the output data stream. Next, setting the disable pin, marked as DIS, to a high logic state, the measurements on all four stops are disabled. On the other hand, the reference clock is not affected, and internal reference measurements are continued. Apart from the mikroBUS™ socket, these signals can also be found on the middle header, grouped with the reference clock pin. 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.

TDC 2 Click hardware overview image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Used MCU Pins

mikroBUS™ mapper

Reference Index Reset
PA0
AN
NC
NC
RST
SPI Chip Select
PD4
CS
SPI Clock
PC6
SCK
SPI Data OUT
PC5
MISO
SPI Data IN
PC4
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
STOP Disable
PB0
PWM
Interrupt
PA6
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

TDC 2 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PICXXX 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 image step 5 hardware assembly
Necto image step 6 hardware assembly
PIC18F57Q43 Curiosity 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

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for TDC 2 Click driver.

Key functions:

  • tdc2_read_results TDC 2 results data reading function.

  • tdc2_start_measuring TDC 2 start measuring function.

  • tdc2_set_resolution TDC 2 set resolution function.

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 TDC 2 Click example
 *
 * # Description
 * This library contains API for TDC 2 Click driver. 
 * The library initializes and defines the SPI bus drivers to 
 * write and read data from registers, as well as the default 
 * configuration for a reading time between two STOP signals.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver after that resets the device and 
 * performs default configuration and sets the device in read mode.

 *
 * ## Application Task
 * This example demonstrates the use of the TDC 2 Click board by 
 * measuring the time between two STOP signals. This example is set up to
 * generate stop signals until FIFO fil's up which is indicated by interrupt pin going to low state.
 * After that FIFO buffer is completely emptied by reading, and that data is used to calculate 
 * the time between STOP signals.
 *
 * @note
 * In order to test this example, you will need to connect STOP1 with the DIS pin. Disable pin is 
 * disabled by software and it isn't going to affect the working state of the TDC 2 Click Bord.
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "tdc2.h"

static tdc2_t tdc2;
static log_t logger;

/**
 * @brief Dev generate stop signal function.
 * @details This function generates the stop signal by toggling DIS pin.
 * @param[out] cfg : Click configuration structure.
 * See #tdc2_cfg_t object definition for detailed explanation.
 * @return Nothing.
 * @note DIS pin ( Disable STOP channels) is disabled by software and isn't affecting the example.
 */
void dev_generate_stop( tdc2_t *ctx );

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    tdc2_cfg_t tdc2_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.
    tdc2_cfg_setup( &tdc2_cfg );
    TDC2_MAP_MIKROBUS( tdc2_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == tdc2_init( &tdc2, &tdc2_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( TDC2_ERROR == tdc2_default_cfg ( &tdc2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    tdc2_start_measuring ( &tdc2 );
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    uint32_t reference_index [ 18 ] = { 0 };
    uint32_t stop_result [ 18 ] = { 0 };
    uint8_t cnt = 0;
    
    tdc2_reset_index( &tdc2 );
    Delay_ms( 10 );
    
    while ( tdc2_get_int_state( &tdc2 ) == 1 )
    {
        dev_generate_stop( &tdc2 );
        Delay_ms( 100 );
    }
    
    while ( tdc2_get_int_state( &tdc2 ) == 0 )
    {
        tdc2_read_results( &tdc2, TDC2_REG_INDEX_CH1_BYTE3, &reference_index[ cnt ], &stop_result[ cnt ] );
        
        log_printf( &logger, "CH1: Reference Index[%d]: %lu, Stop Result[%d]: %lu \r\n", ( uint16_t ) cnt, 
                    reference_index[ cnt ], ( uint16_t ) cnt, stop_result[ cnt ] ); 
        Delay_ms( 10 ); 
        
        if ( cnt )
        {
            uint32_t time = 0;
            tdc2_get_time_between_stops ( &tdc2, stop_result[ cnt - 1 ], reference_index[ cnt - 1 ],
                                          stop_result[ cnt ], reference_index[ cnt ], &time );
            log_printf( &logger, "Time between STOP %d and STOP %d is %lu ms \r\n", 
                        ( uint16_t ) ( cnt - 1 ), ( uint16_t ) cnt, time / TDC2_uS_TO_mS ); 
            Delay_ms( 10 );
        }
        cnt++;
    }
    log_printf( &logger, "---------------------------------------------- \r\n" ); 
}

void main ( void )
{
    application_init( );

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

void dev_generate_stop( tdc2_t *ctx )
{
    digital_out_high( &ctx->dis );
    Delay_ms( 1 );
    digital_out_low( &ctx->dis );
}

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

Additional Support

Resources

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