Expand the number of input/output (I/O) pins in your system with PCAL9714 and PIC18F57Q43

Expand 18 Click is based on the PCAL9714, an ultra low-voltage translating 14-bit SPI I/O expander from NXP. This board enables I/O expansion for a wide range of microcontroller (MCU) families, offering additional GPIO (General Purpose Input/Output) pins with minimal interconnection requirements. It operates via the SPI interface, making it compatible with various MCUs. Its ultra-low voltage interface supports direct communication with MCUs operating at voltages as low as 1.1V, while simultaneously interfacing with I/O devices at different voltage levels. This I/O expanding solution is particularly suited for tasks that require interfacing with sensors, push buttons, keypads, and other input devices, all while ensuring that power consumption and pin usage are kept to a minimum. The PCAL9714 used in Expand 18 Click features an integrated level-shifting capability, providing exceptional flexibility in systems with mixed power supplies. It operates with two distinct power supplies: one for its logic side and one for its core circuits. The logic side can be powered by either the 3.3V or 5V mikroBUS™ power rails, selectable via the VCC SEL jumper. The core circuits, however, can draw power either from the 3.3V

mikroBUS™ rail or an external power source connected to the VEXT pins, supporting voltages from 1.65V to 5V. This core circuit power source is adjustable via the VDDP SEL jumper, ensuring optimal voltage management for diverse application needs. Expand 18 Click communicates with the host MCU via a 4-wire SPI interface, supporting a maximum clock frequency of 5MHz, ensuring efficient and reliable data transfer. In addition to the SPI interface, the board includes an active-low RST pin to reset the PCAL9714 in case of time-outs or operational issues. The power-on reset restores the registers to their default state and reinitializes the SPI state machine, while the RST pin allows the same reset process without requiring a complete power cycle. The PCAL9714 also incorporates Agile I/O features, enhancing the functionality of the I/Os. These features include programmable output drive strength, latchable inputs, programmable pull-up and pull-down resistors, maskable interrupts, an interrupt status register, and configurable open-drain or push-pull outputs. Additionally, Agile I/O Plus offers interrupts specified by level or edge, with the ability to clear them individually without affecting other events. The interrupt (INT) pin is triggered when an input

state changes from its corresponding Input Port register state, alerting the host MCU of the change. At power-on, all I/Os are configured as inputs. However, the host MCU can easily reconfigure them as either inputs or outputs by writing to the appropriate I/O configuration bits. Data for each I/O is stored in the corresponding input or output register, and the Input Port register’s polarity can be inverted through the Polarity Inversion register, eliminating the need for external logic gates. Programmable pull-up and pull-down resistors further reduce the need for discrete components. The expander outputs offer 25mA sink capabilities, allowing for direct LED driving while maintaining low current consumption. Additionally, the PCAL9714 features a hardware pin for SPI-bus address programming, accessible via the ADDR SEL jumper, enabling up to four devices to share the same SPI bus. 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.

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.