Your shield against interference for flawless USB communication based on ISOUSB111 and ATmega2560
Redefining USB to UART connectivity for a smoother data exchange
Published Feb 14, 2024
Click board™
USB UART ISO Click
Dev. board
Arduino Mega 2560 Rev3
Compiler
NECTO Studio
MCU
ATmega2560
Complete USB-to-UART isolated solution for engineers and developers working on projects that demand secure and reliable data communication.
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Hardware Overview
How does it work?
USB UART ISO Click is based on the ISOUSB111, a full/low-speed isolated USB repeater from Texas Instruments. It is a galvanically isolated USB 2.0 repeater that supports automatic speed connection detection, reflection of pull-ups/pull-downs, and link power management. The repeater isolates D+ and D- USB bus lines and supports automatic role reversal. This means that, after disconnection, if a new connection is detected on the upstream-facing port, then the upstream and downstream port definitions are reversed. This device uses a silicon dioxide insulation barrier with a withstand voltage of up to 5000VRMS and a working voltage of 1500VRMS, thus protecting from high voltages and preventing noise currents
from the bus entering the local ground. This USB repeater also comes with a pair of unpopulated headers for testing purposes for both sides of the isolation barrier. Both headers contain a GND (for both sides), a powered-up indicator pin (V1OK or V2OK), and power supply pins for both sides. USB UART ISO Click is equipped with a USB type C connector, which can connect a USB device to a host MCU over the UART bridge and a USB isolated repeater. The FT232R is a well-known UART bridge chip on which the entire USB protocol is handled on the chip. There is driver support for all common operating systems. The UART chip comes with a pair of UART RX and TX LEDs to visually present UART data flow. USB
UART ISO Click uses a standard UART interface to establish communication of the connected USB device with the host MCU over the UART bridge and an isolated USB repeater. In addition, the UART flow control pins RTS and CTS are available. Additionally, there is an SLP pin for Sleep mode control and a PWR pin as a power enable pin. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VIO 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 for further development.
Features overview
Development board
Arduino Mega 2560 is a robust microcontroller platform built around the ATmega 2560 chip. It has extensive capabilities and boasts 54 digital input/output pins, including 15 PWM outputs, 16 analog inputs, and 4 UARTs. With a 16MHz crystal
oscillator ensuring precise timing, it offers seamless connectivity via USB, a convenient power jack, an ICSP header, and a reset button. This all-inclusive board simplifies microcontroller projects; connect it to your computer via USB or power it up
using an AC-to-DC adapter or battery. Notably, the Mega 2560 maintains compatibility with a wide range of shields crafted for the Uno, Duemilanove, or Diecimila boards, ensuring versatility and ease of integration.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
256
Silicon Vendor
Microchip
Pin count
100
RAM (Bytes)
8192
You complete me!
Accessories
Click Shield for Arduino Mega comes equipped with four mikroBUS™ sockets, with two in the form of a Shuttle connector, allowing all the Click board™ devices to be interfaced with the Arduino Mega board with no effort. Featuring an AVR 8-bit microcontroller with advanced RISC architecture, 54 digital I/O pins, and Arduino™ compatibility, the Arduino Mega board offers limitless possibilities for prototyping and creating diverse applications. This board is controlled and powered conveniently through a USB connection to program and debug the Arduino Mega board efficiently out of the box, with an additional USB cable connected to the USB B port on the board. Simplify your project development with the integrated ATmega16U2 programmer and unleash creativity using the extensive I/O options and expansion capabilities. There are eight switches, which you can use as inputs, and eight LEDs, which can be used as outputs of the MEGA2560. In addition, the shield features the MCP1501, a high-precision buffered voltage reference from Microchip. This reference is selected by default over the EXT REF jumper at the bottom of the board. You can choose an external one, as you would usually do with an Arduino Mega board. There is also a GND hook for testing purposes. Four additional LEDs are PWR, LED (standard pin D13), RX, and TX LEDs connected to UART1 (mikroBUS™ 1 socket). This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino Mega board with Click Shield for Arduino Mega, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
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 Arduino Mega 2560 Rev3 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 USB UART ISO Click driver.
Key functions:
usbuartiso_generic_write- USB UART ISO data writing function.usbuartiso_generic_read- USB UART ISO data reading 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 USB UART ISO Click Example.
*
* # Description
* This example demonstrates the use of USB UART ISO click board by processing
* the incoming data and displaying them on the USB UART.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration.
*
* ## Application Task
* Any data which the host PC sends via UART Terminal
* will be sent over USB to the click board and then it will be read and
* echoed back by the MCU to the PC where the terminal program will display it.
* Results are being sent to the UART Terminal, where you can track their changes.
*
* @author Nenad Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "usbuartiso.h"
static usbuartiso_t usbuartiso;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
usbuartiso_cfg_t usbuartiso_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.
usbuartiso_cfg_setup( &usbuartiso_cfg );
USBUARTISO_MAP_MIKROBUS( usbuartiso_cfg, MIKROBUS_1 );
if ( UART_ERROR == usbuartiso_init( &usbuartiso, &usbuartiso_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
usbuartiso_default_cfg ( &usbuartiso );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
char rx_data = 0;
if ( usbuartiso_generic_read ( &usbuartiso, &rx_data, 1 ) )
{
if ( usbuartiso_generic_write ( &usbuartiso, &rx_data, 1 ) )
{
log_printf( &logger, "%c", rx_data );
}
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
Additional Support
Resources
Category:USB
