Intermediate
30 min

Optimize pin utilization and reduce board complexity with CY8C9540A and ATmega1284

Upgrade your I/O game!

EXPAND 7 Click with EasyAVR v7

Published Sep 23, 2023

Click board™

EXPAND 7 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega1284

Experience the versatility of our I/O pin expansion solution, tailored to provide you with the flexibility and control needed to optimize your projects, reduce complexity, and enhance connectivity

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Hardware Overview

How does it work?

EXPAND 7 Click is based on the CY8C9540A, 40-bit I/O expander with EEPROM, and eight independently configurable 8-bit PWM outputs from Infineon. The main blocks of the CY8C9540A include the control unit, PWMs, EEPROM, and I/O ports. The I/O expander's data pins can be independently assigned as inputs, outputs, or PWM outputs and can be configured as open-drain or collector, strong drive (10 mA source, 25 mA sink), resistively pulled up or down, or high impedance which can be selected in the Port Drive Mode register. It operates as two I2C peripheral devices, where the first device is a multi-port I/O expander (single I2C address to access all ports through registers), and the second is a serial EEPROM with 11 Kbyte address space. Configuration and output register settings are storable as the user defaults in a dedicated section

of the EEPROM. If user defaults were stored in EEPROM, they are restored to the ports at the Power-Up sequence. The EEPROM is byte-readable and supports byte-by-byte writing. A pin 3 of Port 2 on this Click board™ can be configured as an EEPROM Write Disable (WD) input that blocks write operations when set high. The configuration registers can also turn off EEPROM operations. EXPAND 7 Click communicates with MCU using the standard I2C 2-Wire interface with a maximum frequency of 100kHz. The CY8C9540A has, by default, two possible I2C slave address formats: the first is used to access the multi-port device, and the second is to access the EEPROM. This selection of I2C slave addresses is performed by setting the logic level on the A0 pin of the CY8C9540A, which can be done using the SMD jumper labeled ADDR SEL. It also generates a

programmable interrupt signal routed on the INT pin of the mikroBUS™, which can inform the system master that there is incoming data on its ports or that the PWM output state has changed. The reset signal routed on the RST pin of the mikroBUS™ socket is similar to the POR (Power-ON Reset) function. When the CY8C9540A is held in Reset, all In and Out pins are held at their default High-Z State. 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.

EXPAND 7 Click top side image
EXPAND 7 Click bottom side image

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.

EasyAVR v7 horizontal image

Microcontroller Overview

MCU Card / MCU

ATmega1284

Architecture

AVR

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

16384

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
PA6
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PD2
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PC0
SCL
I2C Data
PC1
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

EXPAND 7 Click Schematic 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.

EasyAVR v7 front image hardware assembly
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 image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
EasyPIC PRO v7a Display Selection Necto Step hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image 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 7 Click driver.

Key functions:

  • expand7_reset - Reset function

  • expand7_write_all - Set all OUTPUT pins' logic levels function

  • expand7_write_pin - Set a single OUTPUT pin's logic level 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 
 * \brief Expand7 Click example
 * 
 * # Description
 * This example demonstrates the use of the EXPAND 7 click.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initalizes I2C driver and makes an initial log.
 * 
 * ## Application Task  
 * This example shows the capabilities of the EXPAND 7 click by toggling 
 * each of the 40 available pins.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "expand7.h"

// ------------------------------------------------------------------ VARIABLES

static expand7_t expand7;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    expand7_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.
    expand7_cfg_setup( &cfg );
    EXPAND7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    expand7_init( &expand7, &cfg );
    Delay_ms ( 100 );
    
    log_printf( &logger, "------------------- \r\n" );
    log_printf( &logger, "   EXPAND 7 click   \r\n" );
    log_printf( &logger, "------------------- \r\n" );
}

void application_task ( void )
{
    expand7_write_all ( &expand7, 0xFF );
    log_printf( &logger, "All pins set to HIGH logic level!\r\n" );
    log_printf( &logger, "---------------------------------\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    for ( uint8_t pin_num = 0; pin_num < 40; pin_num++ )
    {
        expand7_write_pin( &expand7, pin_num, EXPAND7_LOW );
        log_printf( &logger, "Pin %u is set to LOW logic level!\r\n", ( uint16_t ) pin_num );
        Delay_ms ( 300 );
    }
    log_printf( &logger, "---------------------------------\r\n" );
    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 
 * \brief Expand7 Click example
 * 
 * # Description
 * This example demonstrates the use of the EXPAND 7 click.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initalizes I2C driver and makes an initial log.
 * 
 * ## Application Task  
 * This example shows the capabilities of the EXPAND 7 click by toggling 
 * each of the 40 available pins.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "expand7.h"

// ------------------------------------------------------------------ VARIABLES

static expand7_t expand7;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    expand7_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.
    expand7_cfg_setup( &cfg );
    EXPAND7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    expand7_init( &expand7, &cfg );
    Delay_ms ( 100 );
    
    log_printf( &logger, "------------------- \r\n" );
    log_printf( &logger, "   EXPAND 7 click   \r\n" );
    log_printf( &logger, "------------------- \r\n" );
}

void application_task ( void )
{
    expand7_write_all ( &expand7, 0xFF );
    log_printf( &logger, "All pins set to HIGH logic level!\r\n" );
    log_printf( &logger, "---------------------------------\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    for ( uint8_t pin_num = 0; pin_num < 40; pin_num++ )
    {
        expand7_write_pin( &expand7, pin_num, EXPAND7_LOW );
        log_printf( &logger, "Pin %u is set to LOW logic level!\r\n", ( uint16_t ) pin_num );
        Delay_ms ( 300 );
    }
    log_printf( &logger, "---------------------------------\r\n" );
    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

Additional Support

Resources

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