Increase the number of ATmega644P’s I/O ports with CAT9555

More I/Os, more fun!

Published Apr 18, 2023

Click board™

Expand 14 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega644P

Boost your microcontroller's capabilities with a versatile and trustworthy port expander

Hardware Overview

How does it work?

Expand 14 Click is based on the CAT9555, a general-purpose I/O expander from ON Semiconductor. It contains two 8-bit configuration ports (input or output), input, output, and polarity inversion registers, alongside an I2C-compatible serial interface, where any of the sixteen I/Os can be configured as an input or output by writing to the configuration register. This port expander represents a simple solution when additional I/Os are needed while keeping interconnections to a minimum; particularly great for sensors, power switches, LEDs, pushbuttons, and fans. Each I/O port is 5V input tolerant, with a high current

I/O drive sink of up to 25mA and an I/O source of up to 10mA, maximum. Additionally, each I/O port is compatible with logic thresholds of 2.5V, 3.3V, and 5V. This Click board™ communicates with MCU using the standard I2C 2-Wire interface with a maximum clock frequency of 400kHz. The CAT9555 has a 7-bit slave address with the first four MSBs fixed to 0100. The address pins A0, A1, and A2 are programmed by the user and determine the value of the last three LSBs of the slave address, which can be selected by positioning onboard SMD jumpers labeled as ADDR SEL to an appropriate position marked as 0 or 1.

Besides, it also features an active-low interrupt feature, routed to the INT pin of the mikroBUS™ socket, indicating to the host controller that an input state has been changed. 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. However, the 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

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)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

4096

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

Interrupt

PD2

INT

I2C Clock

PC0

SCL

I2C Data

PC1

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

EasyAVR v7 Access DIP MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection Necto Step hardware assembly

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 Expand 14 Click driver.

Key functions:

expand14_set_pin_direction This function sets the direction of the selected pins.
expand14_set_all_pins_value This function sets the value of all output pins.
expand14_read_port_value This function reads the value of the selected port input pins.

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 Expand14 Click example
 *
 * # Description
 * This example demonstrates the use of Expand 14 click board by setting and reading 
 * the ports state.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets 
 * the port 0 as output and the port 1 as input.
 *
 * ## Application Task
 * Sets the pins of the port 0 and then reads the status of both ports and 
 * displays the results on the USB UART approximately once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "expand14.h"

static expand14_t expand14;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    expand14_cfg_t expand14_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.
    expand14_cfg_setup( &expand14_cfg );
    EXPAND14_MAP_MIKROBUS( expand14_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == expand14_init( &expand14, &expand14_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( EXPAND14_ERROR == expand14_default_cfg ( &expand14 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    uint8_t port_value = 0;
    for ( uint16_t pin_num = EXPAND14_PIN_0_MASK; pin_num <= EXPAND14_PIN_7_MASK; pin_num <<= 1 )
    {
        expand14_set_all_pins_value( &expand14, pin_num );
        
        expand14_read_port_value( &expand14, EXPAND14_PORT_0, &port_value );
        log_printf( &logger, " Status port 0 (output): 0x%.2X\r\n", ( uint16_t ) port_value );
        
        expand14_read_port_value( &expand14, EXPAND14_PORT_1, &port_value );
        log_printf( &logger, " Status port 1 (input) : 0x%.2X\r\n\n", ( uint16_t ) port_value );
        Delay_ms ( 1000 );
    }
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

// ------------------------------------------------------------------------ END

/*!
 * @file main.c
 * @brief Expand14 Click example
 *
 * # Description
 * This example demonstrates the use of Expand 14 click board by setting and reading 
 * the ports state.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets 
 * the port 0 as output and the port 1 as input.
 *
 * ## Application Task
 * Sets the pins of the port 0 and then reads the status of both ports and 
 * displays the results on the USB UART approximately once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "expand14.h"

static expand14_t expand14;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    expand14_cfg_t expand14_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.
    expand14_cfg_setup( &expand14_cfg );
    EXPAND14_MAP_MIKROBUS( expand14_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == expand14_init( &expand14, &expand14_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( EXPAND14_ERROR == expand14_default_cfg ( &expand14 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    uint8_t port_value = 0;
    for ( uint16_t pin_num = EXPAND14_PIN_0_MASK; pin_num <= EXPAND14_PIN_7_MASK; pin_num <<= 1 )
    {
        expand14_set_all_pins_value( &expand14, pin_num );
        
        expand14_read_port_value( &expand14, EXPAND14_PORT_0, &port_value );
        log_printf( &logger, " Status port 0 (output): 0x%.2X\r\n", ( uint16_t ) port_value );
        
        expand14_read_port_value( &expand14, EXPAND14_PORT_1, &port_value );
        log_printf( &logger, " Status port 1 (input) : 0x%.2X\r\n\n", ( uint16_t ) port_value );
        Delay_ms ( 1000 );
    }
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

// ------------------------------------------------------------------------ END

/*!
 * @file main.c
 * @brief Expand14 Click example
 *
 * # Description
 * This example demonstrates the use of Expand 14 click board by setting and reading 
 * the ports state.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets 
 * the port 0 as output and the port 1 as input.
 *
 * ## Application Task
 * Sets the pins of the port 0 and then reads the status of both ports and 
 * displays the results on the USB UART approximately once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "expand14.h"

static expand14_t expand14;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    expand14_cfg_t expand14_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.
    expand14_cfg_setup( &expand14_cfg );
    EXPAND14_MAP_MIKROBUS( expand14_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == expand14_init( &expand14, &expand14_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( EXPAND14_ERROR == expand14_default_cfg ( &expand14 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    uint8_t port_value = 0;
    for ( uint16_t pin_num = EXPAND14_PIN_0_MASK; pin_num <= EXPAND14_PIN_7_MASK; pin_num <<= 1 )
    {
        expand14_set_all_pins_value( &expand14, pin_num );
        
        expand14_read_port_value( &expand14, EXPAND14_PORT_0, &port_value );
        log_printf( &logger, " Status port 0 (output): 0x%.2X\r\n", ( uint16_t ) port_value );
        
        expand14_read_port_value( &expand14, EXPAND14_PORT_1, &port_value );
        log_printf( &logger, " Status port 1 (input) : 0x%.2X\r\n\n", ( uint16_t ) port_value );
        Delay_ms ( 1000 );
    }
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

// ------------------------------------------------------------------------ END