The Expand 14 Click Board™ as its foundation uses 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.
The Expand 14 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 labelled 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.
The Expand 14 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 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.
| Type | Port expander |
| Applications | Can be used for sensors, power switches, LEDs, pushbuttons, and fans |
| On-board modules | CAT9555 - general-purpose I/O expander from ON Semiconductor |
| Key Features | 16 I/O Pins that default to inputs at Power−Up, 5V Tolerant I/Os, high drive capability, individual I/O configuration, polarity inversion register, interrupt, and more |
| Interface | I2C |
| Compatibility | mikroBUS |
| Click board size | L (57.15 x 25.4 mm) |
| Input Voltage | 3.3V or 5V |
This table shows how the pinout of the Expand 14 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 | INT | Interrupt | |
| 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 |
| Label | Name | Default | Description |
|---|---|---|---|
| LD1 | PWR | - | Power LED Indicator |
| JP1 | VCC SEL | Left | Logic Level Voltage Selection 3V3/5V: Left position 3V3, Right position 5V |
| JP2-JP4 | ADDR SEL | Left | I2C Address Selection 0/1: Left position 0, Right position 1 |
| J1-J2 | P0-P1 | Populated | I/O Expander Ports |
| Description | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Supply Voltage | 3.3 | - | 5 | V |
| Output Current - Source/Sink | - | 10/24 | - | mA |
| Number of I/Os | - | - | 16 | pins |
| Operating Temperature Range | -40 | +25 | +85 | °C |
We provide a library for the Expand 14 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 The package Manager (recommended), downloaded from their LibStock™or found on the MikroE Github account.
This library contains API for the Expand 14 Click Board™ driver.
Key functions
expand14_set_pin_directionThis function sets the direction of the selected pins.
expand14_set_all_pins_valueThis function sets the value of all output pins.
expand14_read_port_valueThis function reads the value of the selected port input pins.
This example demonstrates the use of the Expand 14 Click Board™ by setting and reading the ports state.
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%.2Xrn", ( uint16_t ) port_value );
expand14_read_port_value( &expand14, EXPAND14_PORT_1, &port_value );
log_printf( &logger, " Status port 1 (input) : 0x%.2Xrnn", ( uint16_t ) port_value );
Delay_ms( 1000 );
}
}
The full application code, and ready to use projects can be installed directly from NECTO Studio The package Manager (recommended), downloaded from ourLibStock™or found on the MikroE Github account.
Other MikroE Libraries used in the example:
Depending on the development board you are using, you may need a USB UART Click Board™,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.
The Expand 14 Click Board™ is supported withmikroSDK- 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.
- condition: new - custom_product: false - key_feature_2: 16 I/O Pins that default to inputs at Power−Up, 5V Tolerant I/Os, high drive capability, individual I/O configuration, polarity inversion register, interrupt, and more - key_feature_3: Based on the CAT9555 - general-purpose I/O expander from ON Semiconductor - key_feature_4: Can be used for sensors, power switches, LEDs, pushbuttons, and fans - key_feature_5: mikroBUS: I2C Interface - device_vendor: onsemi - device_type: CAT9555YI-T2 - warranty: 12 months - brand: MikroE - manufacturer: Mikroelektronika d.o.o. - target_keyword: Expand 14 Click Board - brands: gid://shopify/Metaobject/56256004319 - breadcrumbs: ["gid://shopify/Collection/447955239135","gid://shopify/Collection/241680580797","gid://shopify/Collection/279382950077","gid://shopify/Collection/279383179453"] - customhs_code: 847330 - detailed_description: {"type":"root","children":[{"type":"heading","level":3,"children":[{"type":"text","value":"How Does The Expand 14 Click Board™ Work?"}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"Expand 14 Click Board™","bold":true,"italic":true},{"type":"text","value":" as its foundation uses 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."}]},{"type":"paragraph","children":[{"type":"text","value":""}]},{"type":"paragraph","children":[{"type":"text","value":"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."}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"Expand 14 Click Board™","bold":true},{"type":"text","value":" 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 labelled as ADDR SEL to an appropriate position marked as 0 or 1."}]},{"type":"paragraph","children":[{"type":"text","value":"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."}]},{"type":"paragraph","children":[{"type":"text","value":"The "},{"type":"text","value":"Expand 14 Click Board™","bold":true},{"type":"text","value":" 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 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."}]},{"type":"heading","level":3,"children":[{"type":"text","value":"SPECIFICATIONS"}]},{"type":"paragraph","children":[{"type":"text","value":"Type\nPort expander\nApplications\nCan be used for sensors, power switches, LEDs, pushbuttons, and fans\nOn-board modules\nCAT9555 - general-purpose I/O expander from ON Semiconductor\nKey Features\n16 I/O Pins that default to inputs at Power−Up, 5V Tolerant I/Os, high drive capability, individual I/O configuration, polarity inversion register, interrupt, and more\nInterface\nI2C\nCompatibility\nmikroBUS\nClick board size\nL (57.15 x 25.4 mm)\nInput Voltage\n3.3V or 5V"}]},{"type":"heading","level":3,"children":[{"type":"text","value":"PINOUT DIAGRAM"}]},{"type":"paragraph","children":[{"type":"text","value":"This table shows how the pinout of the "},{"type":"text","value":"Expand 14 Click Board™","bold":true},{"type":"text","value":" corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns)."}]},{"type":"paragraph","children":[{"type":"text","value":"Notes\nPin\nPin\nNotes\nNC\n1\nAN\nPWM\n16\nNC\nNC\n2\nRST\nINT\n15\nINT\nInterrupt\nNC\n3\nCS\nRX\n14\nNC\nNC\n4\nSCK\nTX\n13\nNC\nNC\n5\nMISO\nSCL\n12\nSCL\nI2C Clock\nNC\n6\nMOSI\nSDA\n11\nSDA\nI2C Data\nPower Supply\n3.3V\n7\n3.3V\n5V\n10\n5V\nPower Supply\nGround\nGND\n8\nGND\nGND\n9\nGND\nGround"}]},{"type":"heading","level":3,"children":[{"type":"text","value":"ONBOARD SETTINGS AND INDICATORS"}]},{"type":"paragraph","children":[{"type":"text","value":"Label\nName\nDefault\nDescription\nLD1\nPWR\n-\nPower LED Indicator\nJP1\nVCC SEL\nLeft\nLogic Level Voltage Selection 3V3/5V: Left position 3V3, Right position 5V\nJP2-JP4\nADDR SEL\nLeft\nI2C Address Selection 0/1: Left position 0, Right position 1\nJ1-J2\nP0-P1\nPopulated\nI/O Expander Ports"}]},{"type":"heading","level":3,"children":[{"type":"text","value":"EXPAND 14 CLICK ELECTRICAL SPECIFICATIONS"}]},{"type":"paragraph","children":[{"type":"text","value":"Description\nMin\nTyp\nMax\nUnit\nSupply Voltage\n3.3\n-\n5\nV\nOutput Current - Source/Sink\n-\n10/24\n-\nmA\nNumber of I/Os\n-\n-\n16\npins\nOperating Temperature Range\n-40\n+25\n+85\n°C"}]},{"type":"heading","level":3,"children":[{"type":"text","value":" "}]}]} - summary:The Expand 14 Click Board™ is a compact add-on board that contains a multi-port I/O expander. This board features the CAT9555, a CMOS device that provides 16-bit parallel input/output port expansion from ON Semiconductor. The CAT9555 contains two 8-bit configuration ports (input or output), input, output, and polarity inversion registers, alongside an I2C-compatible serial interface. Any sixteen I/Os can be configured as an input or output by writing to the configuration register. It also features an active-low interrupt output, indicating to the host controller that an input state has been changed. This Click board™ provides a simple solution when additional I/Os are needed while keeping interconnections to a minimum in system monitoring applications, industrial controllers, portable equipment, and many more.
The Expand 14 Click Board™ is supported by a mikroSDK compliant library, including functions that simplify software development. This Click board™ comes as a thoroughly tested product, ready to be used on a system equipped with the mikroBUS™ socket.