PX-41CX Design Requirements:

• Ease of Assembly: All through-hole parts for easy handling and soldering.
• Off-the-Shelf Parts: Utilizes readily available components for easy sourcing and replacement.
• Enhanced Clock/Timer: Resolution of 250ms, an improvement over the original 100ms.
• Increased Speed: Runs much faster than the original HP-41CX.
• Full RAM: 319 registers.
• Full Extended Memory: 600 registers.
• Continuous Memory Retention: Retains memory even when the calculator is turned off.
• Auto Power Off: Automatically powers off to save battery life.
• Advanced Microcontroller: Powered by a single AVR128DA 8-bit microcontroller, with selectable speeds from 8MHz to 32MHz.
• Audible Feedback: Equipped with a speaker for audible keypress feedback.
• High-Quality Display: Ultra-low power monochrome reflective LCD with a resolution of 250x122 pixels (no backlight).
• Extensive ROM Storage: Can store up to twelve 4K ROM modules.
• Real-Time Clock: Includes a real-time clock using a 32.768KHz crystal.
• Power Options: Operates on a single CR2032 3V battery or can be powered via USB cable.
• Low Power Consumption: Designed for efficiency.
• Connectivity: Supports Serial RS232 connectivity for flashing and data transfer, using a standard female USB mini B connector.
• Tactile Switches: Features tactile switches with a force of 70gf.
• Color Keycaps: Includes color keycaps for easy identification.

YouTube video by Calculator Clique.