Application examples for hardware designCD4026 decade counter with a built-in driver for a common-cathode seven-segment display. One pushbutton advances the count from 0 to 9 and a second one clears it. No microcontroller and no external decoder — the chip does both jobs on its own.
CD4017 decade counter driven by hand with a pushbutton. Each press moves the active output to the next LED (D1 to D10), and a second button clears the count back to zero. A classic way to see CMOS logic in action without an oscilloscope.
USB to asynchronous TTL serial port converter based on the WCH CH340G in SOP-16, with a 12 MHz crystal and bus-powered from USB.
A concise guide to the CH9329 from Nanjing Qinheng Microelectronics — pinout, operating modes and serial communication modes for emulating a USB keyboard, mouse and custom HID device.
A concise guide to the TM1637 from Titan Micro Electronics — pinout, internal operation and the two-wire communication protocol used to drive 7-segment displays and read a keypad matrix.