Philips P89LPC938, User Manual

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© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual Rev. 03 — 7 June 2005 23 of 139
Philips Semiconductors
UM10119
P89LPC938 User manual
– Fixed channel, single conversion mode
– Fixed channel, continuous conversion mode
– Auto scan, single conversion mode
– Auto scan, continuous conversion mode
– Dual channel, continuous conversion mode
– Single step mode
•
Three conversion start modes
– Timer triggered start
– Start immediately
– Edge triggered
•
10-bit conversion time of
4 µ
s at an A/D clock of 9 MHz
•
Interrupt or polled operation
•
High and low boundary limits interrupt
•
Clock divider
•
Power down mode
3.2.1 A/D operating modes
3.2.1.1 Fixed channel, single conversion mode
A single input channel can be selected for conversion. A single conversion will be
performed and the result placed in the result register pair which corresponds to the
selected input channel (see
Table 7 ). An interrupt, if enabled, will be generated after the
conversion completes. The input channel is selected in the ADINS register. This mode is
selected by setting the SCAN0 bit in the ADMODA register.
Fig 8. ADC block diagram.
+
–
comp
DAC1
SAR
8
INPUT
MUX
CONTROL
LOGIC
CCLK
002aab103
Table 7: Input channels and result registers for fixed channel single, auto scan single, and
auto scan continuous conversion modes
Result register Input channel Result register Input channel
AD0DAT0R/L AD00 AD0DAT4R/L AD04