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Philips Semiconductors
Volume 1
17.5 Operation
17.5.1 Hardware-triggered conversion
If the BURST bit in the ADCR is 0 and the START field contains 010-111, the ADC will
start a conversion when a transition occurs on a selected pin or Timer Match signal. The
choices include conversion on a specified edge of any of 4 Match signals, or conversion
on a specified edge of either of 2 Capture/Match pins. The pin state from the selected pad
or the selected Match signal, XORed with ADCR bit 27, is used in the edge detection
logic.
17.5.2 Interrupts
An interrupt request is asserted to the Vectored Interrupt Controller (VIC) when the DONE
bit is 1. Software can use the Interrupt Enable bit for the A/D Converter in the VIC to
control whether this assertion results in an interrupt. DONE is negated when the ADDR is
read.
17.5.3 Accuracy vs. digital receiver
The AIN function must be selected in corresponding Pin Select register (see "Pin Connect
Block" on page 75) in order to get accurate voltage readings on the monitored pin. For pin
hosting an ADC input, it is not possible to have a have a digital function selected and yet
get valid ADC readings. An inside circuit disconnects ADC hardware from the associated
pin whenever a digital function is selected on that pin.
User manual
Rev. 01 — 15 August 2005
UM10139
Chapter 17: A/D Converter
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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