The E2063 Chromatic Tuner & Frequency Counter is a compact module providing a fast and accurate measurement over a wide range of fundamental musical notes (C0 16.34Hz to G#8 6644Hz) or frequencies (0.04Hz to 99,999Hz) along with a +/- 1 to 5 error indication using the equal tempered A4=440Hz scale. The module uses a multi-cycle inverse period measurement algorithm accurate to 20ppm followed by a 64 bit division to provide exceptional resolution. The music note or frequency measurement mode is selectable with either a switch or logic input. A comparator input allows any fundamental waveform for the signal input to be measured. The comparator reference is selectable between an internal 1.8V or an external user defined reference voltage. A serial output is also provided every measurement at 115,200 baud. The backlit display with 0.3" characters operates from +4 to +17V. The 1.1" x 2.75" module is easily mounted with two screws. This module is useful for sound studio instrumentation, electronic music synthesis control panels, and calibration and test equipment for accurate measurement and music note classification of fundamental frequencies.