Beginner
10 min
0

Your shield against interference for flawless USB communication based on ISOUSB111 and PIC24HJ256GP610

Redefining USB to UART connectivity for a smoother data exchange

USB UART ISO Click with UNI Clicker

Published Nov 15, 2023

Click board™

USB UART ISO Click

Development board

UNI Clicker

Compiler

NECTO Studio

MCU

PIC24HJ256GP610

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.

USB UART ISO Click hardware overview image

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

dsPIC

MCU Memory (KB)

256

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

16384

Used MCU Pins

mikroBUS™ mapper

Sleep Mode Control
RB10
AN
NC
NC
RST
UART CTS
RG9
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
FTDI Power Enable
RD0
PWM
UART RTS
RF6
INT
UART TX
RF5
TX
UART RX
RF4
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

USB UART ISO Click Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
UNI Clicker 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
Necto image step 7 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

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

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * @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