2 ATtiny28: The Ideal Solution for Intelligent Remote Control Systems

ATtiny28 is a low-cost, high-performance 8-bit AVR RISC microcontroller with a number of features that makes it well suited for remote control applications. The built-in hardware modulator eases the task of generating the carrier frequency on which a data signal can be modulated. Frequency and duty-cycle are both easily changed by modifying the value residing in the Modulation Control Register MODCR. The high current driver on pin two of port A (PA2) is capable of driving an LED with a minimum of external components. This reduces size and system cost. In Power-down mode, the microcontroller can be configured to wake up on a low level from any pin on Port B. This provides an easy solution for waking up, scanning the keyboard, sending the command, and returning to Power-down mode. This application implements an easy keyboard scanning routine using Port B and Port D.