Track time with laser precision using AS6500 and ATmega644
Sync up - time waits for none
Published May 27, 2023
Click board™
TDC 2 Click
Dev. board
EasyAVR v7
Compiler
NECTO Studio
MCU
ATmega644
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.
Features overview
Development board
EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more
efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)
connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 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.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
64
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
4096
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.
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_resultsTDC 2 results data reading function.tdc2_start_measuringTDC 2 start measuring function.tdc2_set_resolutionTDC 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
