If you have multiple AT89C series chips, you can use one AT89C2051 to build a standalone programmer or a development board for its larger siblings.

Generate up to 4 servo control signals using software PWM. Each servo needs a 20ms frame with a 1–2ms high pulse. Use one timer interrupt to update all outputs sequentially. Add a potentiometer via an external ADC (or use comparator + resistor ladder) for manual control.

Before diving into the projects, it’s worth noting why this chip remains popular despite the rise of Arduino and ESP32:

: Digital tachometers, thermometers, and industrial timers often utilize the analog comparator for signal conditioning. Beginner Gadgets

Best of luck!

Understanding the timing of IR bursts.