Experience ultra-responsive pulse generation with LTC6993-2 and STM32F031K6
“One-shot” pulse generator
Published Oct 01, 2024
Click board™
One Shot Click
Dev. board
Nucleo 32 with STM32F031K6 MCU
Compiler
NECTO Studio
MCU
STM32F031K6
Create accurately timed pulses, and ensure synchronized operations in various systems and devices
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Hardware Overview
How does it work?
One Shot Click is based on the LTC6993-2, a monostable multivibrator (also known as a "one-shot" pulse generator) with a programmable pulse width of 1μs to 33.6 seconds from Analog Devices. The LTC6993-2 is part of the TimerBlox® family of versatile silicon timing devices. A single resistor, RSET, programs an internal master oscillator frequency, setting the LTC6993's time base. The output pulse width is determined by this master oscillator and an internal clock divider, NDIV, programmable to eight settings from 1 to 221. The output pulse is initiated by a transition on the trigger input (TRIG). Each part can be configured to generate positive or negative output pulses. The LTC6993-2 has four versions to provide different trigger signal polarity and retrigger capability. Besides that, LTC6993-2 also offers the ability to dynamically adjust the width of the output pulse via a separate control voltage brought to the SET
pin of the IC. A simple trimmer or potentiometer could be used; however, due to reliability reasons, the AD5241 digital potentiometer is used for that purpose on One Shot Click. The word is also about a 256-position digital potentiometer with a low-temperature coefficient (30 ppm/°C) from Analog Devices. The AD5241 communicates with the microcontroller over the standard I2C interface so that the user can easily control and precisely calculate the output pulse width just by simply setting the wiper value in the AD5241 registers. One Shot Click also contains the multi-turn trimmer wired as a resistor divider between V+ and GND and brought to the DIV pin of the LTC6993-2. The DIV pin is the programmable divider and polarity input. The polarity input, which pin voltage is internally converted into a 4-bit result (DIVCODE). The MSB of DIVCODE (POL) determines the polarity of the OUT pins. When
POL = 0, the output produces a positive pulse. When POL = 1, the output produces a negative pulse. That way, the user can easily set the output pulse width range, and polarity by setting the desired voltage on the trimmer mentioned (VR1). This Click also contains test points to ease the user's access to the referent voltage. One can separate the trimmer from the rest of the circuit using the separation switch (SW1), then precisely set and measure the desired voltage and turn the switch back in the ON position. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used, as a reference, for further development.
Features overview
Development board
Nucleo 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The
board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,
and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M0
MCU Memory (KB)
32
Silicon Vendor
STMicroelectronics
Pin count
32
RAM (Bytes)
4096
You complete me!
Accessories
Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.
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 Nucleo 32 with STM32F031K6 MCU 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 One Shot Click driver.
Key functions:
oneshot_get_resistance- This function reads the resistance data from the AD5241 chiponeshot_digital_read_rst- This function reads the digital signal from the RST pinoneshot_digital_write_cs- This function writes the specified digital signal to the CS pin
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
* \brief OneShot Click example
*
* # Description
* This example shows the user how to configure and use the One Shot click. The click has a
* monostable monovibrator which cam generate a pulse of width between 1μs and 33.6 seconds.
*
* The demo application is composed of two sections :
*
* ## Application Init
* This function initializes and configures the logger and click modules. Resistance data,
* acquired from the AD5241, is displayed at the end of the initialization process.
*
* ## Application Task
* This function triggers one shot every 8 seconds.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "oneshot.h"
// ------------------------------------------------------------------ VARIABLES
static oneshot_t oneshot;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( )
{
log_cfg_t log_cfg;
oneshot_cfg_t cfg;
/**
* 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.
oneshot_cfg_setup( &cfg );
ONESHOT_MAP_MIKROBUS( cfg, MIKROBUS_1 );
oneshot_init( &oneshot, &cfg );
Delay_100ms( );
oneshot_default_cfg( &oneshot );
Delay_100ms( );
log_printf( &logger, " * Resistance: %.1f Ohm\r\n", oneshot_get_resistance( &oneshot ) );
}
void application_task ( )
{
oneshot_digital_write_cs( &oneshot, 1 );
Delay_ms( 1 );
oneshot_digital_write_cs( &oneshot, 0 );
log_printf( &logger, " * One shot triggered \r\n" );
log_printf( &logger, " --------------------------- \r\n" );
Delay_ms( 8000 );
}
void main ( )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
