UM10147_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 28 April 2008
29 of 134
NXP Semiconductors
UM10147
P89LPC952/954 User manual
second channel is placed in result register pair, AD0DAT1R and AD0DAT1L. The first
channel is again converted and its result stored in AD0DAT2R and AD0DAT2L. The
second channel is again converted and its result placed in AD0DAT3R and AD0DAT3L,
etc. (see
). An interrupt is generated, if enabled, after every set of four or eight
conversions (user selectable). This mode is selected by setting the SCC0 bit in the
ADMODA register.
3.2.1.6
Single step mode
This special mode allows ‘single-stepping’ in an auto scan conversion mode. Any
combination of the eight input channels can be selected for conversion. After each
channel is converted, an interrupt is generated, if enabled, and the A/D waits for the next
start condition. The result of each channel is placed in the result register which
corresponds to the selected input channel (See
). May be used with any of the
start modes. This mode is selected by clearing the BURST0, SCC0, and SCAN0 bits in
the ADMODA register.
3.2.2 Conversion mode selection bits
The A/D uses three bits in ADMODA to select the conversion mode. These mode bits are
summarized in
,below. Combinations of the three bits, other than the
combinations shown, are undefined.
Table 9.
Result registers and conversion results for dual channel, continuous conversion
mode
Result register
Contains
AD0DAT0R/L
First channel, first conversion result
AD0DAT1R/L
Second channel, first conversion result
AD0DAT2R/L
First channel, second conversion result
AD0DAT3R/L
Second channel, second conversion result
AD0DAT4R/L
First channel, third conversion result
AD0DAT5R/L
Second channel, third conversion result
AD0DAT6R/L
First channel, fourth conversion result
AD0DAT7R/L
Second channel, fourth conversion result
Table 10.
Conversion mode bits
Burst0
SCC0
Scan0
ADC0 conversion mode
0
0
0
Single step
0
0
1
Fixed channel, single
Auto scan, single
0
1
0
Fixed channel, continuous
Dual channel, continuous
1
0
0
Auto scan, continuous