© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
User manual
Rev. 01 — 12 January 2006
186
Philips Semiconductors
UM10161
Volume 1
Chapter 14: A/D converter
14.5 Operation
14.5.1 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.
14.5.2 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.
14.5.3 Accuracy
vs.
digital
receiver
The AD0 function must be selected in corresponding Pin Select register (see "Pin
Connect Block" on
Section 7.4 “Register description” on page 66
) in order to get accurate
voltage readings on the monitored pin. For the 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.