Achieve reliable movement or rotation encoding with TCUT1600X01 and PIC18F47K40
Decode moves with precision
Published Sep 21, 2023
Click board™
Opto encoder Click
Dev Board
EasyPIC v8
Compiler
NECTO Studio
MCU
PIC18F47K40
Achieve unparalleled levels of precision and accuracy in your motion tracking and control systems
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Hardware Overview
How does it work?
Opto encoder Click is based on the TCUT1600X01, a tall dome dual channel transmissive optical sensor with phototransistor outputs from Vishay. This sensor is equipped with one infrared LED with the wavelength of 950nm, and two phototransistors. These phototransistors are positioned behind two small slits on the sensor, on the opposite side of the LED. They form two separate channels. When the transistors get illuminated by the LED, they become conductive. The collectors of these transistors are connected to the same pin, while their emitters are routed to two separate output pins of the TCUT1600X01 - E1 and E2. This allows the activity on both channels to be detected by the host MCU. Since the signals of these two output channels are not enough to drive pins
on a host MCU, the Click board™ features two additional MOSFETs. These MOSFETs are also used to drive two additional LEDs, which indicate activity of each channel. E1 and E2 pins are routed to the MOSFET gate pins, while the MOSFET drains are routed to the mikroBUS™ PWM and INT pins. These pins are pulled to a LOW logic level by the pull-down resistors, to avoid floating. Signal encoding itself is done by the host MCU. Having two optical sensing channels, Opto Encoder click has the ability of both speed and direction encoding. The most common usage is encoding of the step motor position: a cylinder with slits is physically mounted above the sensor so that the LED can illuminate the phototransistors only through these slits. By rotating this cylinder,
the light beam will be blocked periodically. The single sensor output will be a pulse train, while the cylinder is rotating. Having two photo sensors physically distanced by a small amount, allows the pulse signal of the first sensor to be either delayed or expedited with respect to the pulse on the second sensor, depending on the rotational direction. 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
EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. 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, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any
circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board 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 DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC 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.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC
MCU Memory (KB)
128
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
3728
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.
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.
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.
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".
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.
Software Support
Library Description
This library contains API for Opto encoder Click driver.
Key functions:
optoencoder_getO1- Function for reading O1 stateoptoencoder_init_dev- Initialization functionoptoencoder_get_position- Function for reading the position of the encoder
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
* \brief Opto Encoder Click example
*
* # Description
* This application is used to encode motion or rotation.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes driver and opto encoder.
*
* ## Application Task
* Depending on the direction of the movement it increments/decrements the step counter.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "optoencoder.h"
// ------------------------------------------------------------------ VARIABLES
static optoencoder_t optoencoder;
static log_t logger;
static int16_t old_step = 0;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
optoencoder_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.
optoencoder_cfg_setup( &cfg );
OPTOENCODER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
optoencoder_init( &optoencoder, &cfg );
optoencoder_init_dev( &optoencoder );
}
void application_task ( )
{
int16_t new_step;
new_step = optoencoder_get_position( &optoencoder );
if ( old_step != new_step)
{
log_printf( &logger, "Step: %d \r\n", new_step );
old_step = new_step;
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
