MIKROE Expand 10 Click is a compact add-on board that contains a multi-port I/O expander. This board features the PCAL6524, a 24-bit general-purpose I/O expander providing remote I/O expansion for most MCU’s families via the Fast-mode Plus I2C-serial interface from NXP Semiconductors. The PCAL6524 has a built-in level shifting feature that makes it highly flexible in power supply systems where communication between incompatible I/O voltages is required. It allows seamless communications with next-generation low voltage microprocessors and microcontrollers on the interface and peripherals at a higher voltage on the port side. 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.

Expand 10 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

Expand 10 Click as its foundation uses the PCAL6524, a 24-bit ultra-low-voltage translating general-purpose I/O expander from NXP Semiconductors. This port expander is a simple solution for 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 PCAL6524 has a built-in level shifting feature that makes it highly flexible in power supply systems where communication between incompatible I/O voltages is required.

The PCAL6524 implements Agile I/O features specifically designed to enhance the I/O. These additional features are programmable output drive strength, latchable inputs, programmable pull-up/pull-down resistors, maskable interrupt, interrupt status register, programmable open-drain or push-pull outputs.

Expand 10 Click communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting a Fast Mode Plus operation up to 1MHz. At the Power-On sequence, the I/Os are configured as inputs. However, the host MCU can enable the I/Os as inputs or outputs by writing to the I/O configuration bits. In addition to I2C communication, two GPIO pins connected to the mikroBUS™ socket pins are also used.

The reset pin, routed to the RST pin of the mikroBUS™ socket, is used to place the PCAL6524 registers in their default state, while the interrupt, routed to the INT pin of the mikroBUS™ socket, may be configured as an interrupt to notify the host MCU of incoming data on any port. Besides, it also allows the choice of the least significant bit of its I2C peripheral address by positioning the SMD jumper labeled as ADDR SEL to an appropriate position marked as 1 and 0.

This 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.

• Interface: I²C
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V or 5V
• Maximum Output Current: 25mA
• Maximum Clock Frequency: 1MHz
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +85°C

• Schematic
• PCAL6524 Datasheet
• mikroSDK
• GitHub