Expand 12 Click Board™

How Does The Expand 12 Click Board™ Work?

The Expand 12 Click Board™ as its foundation uses the MAX7300, a general-purpose input/output (GPIO) expander from Maxim Integrated, now part of Analog Devices. This port expander is a simple solution when additional I/Os are needed while keeping interconnections to a minimum, particularly great for system monitoring applications, industrial controllers, portable equipment, and others. The MAX7300 comes in a 28-port configuration, which can be configured to any combination of logic inputs and logic outputs, and default to logic inputs on Power-Up.

Any I/O port can be configured as a push-pull output (sinking 10mA, sourcing 4.5mA) or a Schmitt-trigger logic input. Each input has an individually selectable internal pull-up resis­tor. Additionally, transition detection allows seven ports (from port 24 up to port 30) to be monitored in any maskable combina­tion for changes in their logic status. A detected transition is flagged through a status register bit, as well as an interrupt pin (port 31) if desired.

The Expand 12 Click Board™ communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings with a maximum frequency of 400kHz. Besides, it also allows the choice of the least significant bit of its I2C slave address by positioning the SMD jumpers labeled as ADDR SEL to an appropriate position marked as 1 and 0. This way, the MAX7300 provides the opportunity of the 16 possible different I2C addresses by positioning the SMD jumper to an appropriate position.

The Expand 12 Click Board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the I2C 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.

SPECIFICATIONS

PINOUT DIAGRAM

This table shows how the pinout on the Expand 12 Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
NC	1	AN	PWM	16	NC
NC	2	RST	INT	15	NC
NC	3	CS	RX	14	NC
NC	4	SCK	TX	13	NC
NC	5	MISO	SCL	12	SCL	I2C Clock
NC	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

ONBOARD SETTINGS AND INDICATORS

EXPAND 12 CLICK ELECTRICAL SPECIFICATIONS

Software Support

We provide a library for the Expand 12 Click Board™ as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

The package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe Github account.

Library Description

This library contains API for the Expand 12 Click Board™ driver.

Key functions

• expand12_set_pin_direction  This function sets the direction of the selected pin.

• expand12_set_pin_value  This function sets the logic level of the selected pin.

• expand12_read_all_pins_value  This function reads all pins logic levels.

Example Description

This example demonstrates the use of the Expand 12 Click board™.

 void application_task ( void ) 
 { 
     static uint8_t port_value = 0; 
     static uint32_t pins_status = 0; 

     expand12_set_port_value( &expand12, EXPAND12_PORT_4_7, EXPAND12_ALL_PINS, port_value ); 
     expand12_set_port_value( &expand12, EXPAND12_PORT_8_15, EXPAND12_ALL_PINS, port_value ); 
     expand12_set_port_value( &expand12, EXPAND12_PORT_16_23, EXPAND12_ALL_PINS, port_value++ ); 

     expand12_read_all_pins_value( &expand12, &pins_status ); 
     log_printf( &logger, " Pins status (32-bit) : 0x%.8LXrnn", pins_status ); 
     Delay_ms( 100 ); 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe Github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Expand12

Additional Notes and Information

Depending on the development board you are using, you may need a USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.

MIKROSDK

TheExpand 12 Click Board™ is supported with mikroSDK - MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.