Achieve pixel perfection with SZ420757N and PIC18F57Q43

7x10 R Click is based on two SZ420757N, red LED dot matrix modules from Wuxi Ark. A single LED matrix module is composed of 35 LED elements grouped in rows and columns. The LED elements in one row have their cathodes connected and routed to a single-row pin. The LED elements in one column have their anodes connected and routed to a single-column pin. Multiplexed like this, modules have a fairly low number of pins (12 per module), making them suitable to be driven by shift registers and a decade of counter ICs. The driver circuit consists of two 74HC595 - 8bit, serial input - parallel output shift registers, one CD4017 - a Jonson topology decade counter with ten outputs, and one ULN2003A - an IC with seven integrated Darlington transistor pairs, all

chips produced by Texas Instruments. The shift registers are used to polarize the anodes on the columns of the LED displays. To complete the LED's current path, their cathodes must be connected to the ground. This is where the CD4017 and ULN2003 ICs are used. The ULN2003 IC drives rows of the dot matrix displays by sinking the current on the active row. To activate one of the seven input channels of the ULN2003 IC, the CD4017 decade counter IC is used. The design of the decade counter allows only one row to be active at a time. So, to see the complete picture on an LED matrix, the row scanning has to be fast enough so that the effect called persistent vision takes place. It produces an illusion of a complete image, even if only one row is seen at a time -

because the human eye cannot detect very fast changes in light. 7x10 R Click uses a 4-Wire SPI serial interface of the 74HC595 shift registers to communicate with the host MCU. The shift registers are chained together and can be reset over the RST pin. The clock and the reset inputs of the CD4017 are controlled by the RC and RR pins. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR 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.