ADC PERIPHERAL IN MICROCONTROLLERS

Petr Cesak, Jan Fischer, Jaroslav Roztocil

Abstract

This paper presents an analog-to-digital converter (ADC) embedded as a peripheral in a microcontroller and influence of asynchronous digital input signals on results of ADC conversion. A schematic diagram of a successive approximation (SAR) ADC peripheral analog input circuit in a microcontroller was described and its model was designed. A practical measurement was performed using crosstalk measurement setup that consists of a MCB2100 Evaluation Board with a microcontroller LPC2129 and an external pulse generator triggered by the tested microcontroller. Measurement results proved that errors of DC measurement depend on a type of edge (rising or falling) of a digital input signal, a time when the edge occurs and an internal resistance of a DC source. The errors reached up to +2 LSB (resp. 2 LSB) depending on the edge type.

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IMEKO-IWADC-2008-118.pdf

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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