The most common implementation for analog-to-digital (A/D) conversion among Motorola microcontrollers is the successive approximation (SAR) method. An alternative A/D conversion technique uses the single-slope A/D converter. This application note explains the theory of operation of the single-slope A/D, applies the principles of operation to the single-slope A/D on the MC68HC705JP7, and provides software examples for the control of the A/D system found on this MCU. Comparisons are made with the SAR A/D where appropriate.