Low Power Morse Code ROM and and Transmitter for 70cm ISM Band

A project for ECE 547 “VLSI Design”
Fall Semester 2011 at the
Electrical Engineering Dept. of the
University of Maine

Designed by
Jamie Reinhold

Computer chip

The design, simulation and layout of a low power Morse code Read Only Memory and transmitter are described. The chip uses a band-gap reference circuit to convert a voltage stored onto a capacitor, to a DC power supply that is insensitive to temperature. The band-gap reference powers a variety of clocks used in the timing for 32×4-bit ROM and 32-bit multiplexer; all based from a voltage-controlled oscillator. The output of the ROM and multiplexer is the Morse code representation of UMAINE ECE, which is transmitted by a 433MHz sinusoidal oscillator and off-chip antennae. Logic 1 is represented by oscillation and Logic 0 is no oscillation. Simulations show less than +10mV variation around 1.185V in the band-gap reference output from -50?C to 125?C with a charge on the capacitor ranging from 1.7V to 2.6V. The output of the overall circuit is a 325mV peak-to-peak sinusoid that oscillates at 433MHz (ISM-band frequency), where each character in the Morse code has a 50ms pulse width. Test and verification procedures are outlined and described.

The project report (PDF) contains a description of the project and details of the design and layout.

Fall 2011