DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
457 of 571
NXP Semiconductors
UM10316
Chapter 26: LPC29xx Analog-to-Digital Converter (ADC)
•
The start bit (0): when set to 1 the ADC conversion is started.
•
The stop bit (1): when set to 1 the conversion is stopped at the end of the next scan.
The stop bit being 0 again indicates that the ADC conversion has been stopped at the
end of a scan.
•
The update bit (2): when set to 1 the configuration and resolution are copied to the
ADC clock domain. This is done immediately when the ADC is in IDLE mode. In
continuous mode, copying of the configuration is done at the end of the scan. The
update bit being 0 again indicates that the configuration has been copied to the ADC
domain.
shows the bit assignment of the ADC_CONTROL register.
3.8 ADC status register
The ADC status register consists of two bits.
•
The ADC_STATUS bit (bit 0): this bit indicates whether an ADC scan is in progress
(bit is set to 1) or not (bit is set to 0). When the configuration is set to internal trigger
(ADC_CONFIG[3:0] = 0000) the ADC_STATUS bit will be asserted when the start bit
is set. When the configuration is set to external start triggering, the ADC_STATUS bit
will be asserted when the ADC conversion is started as a result of the selected
external start event. The ADC_STATUS bit is set to logic 0 when the conversion is
stopped and the results are available in the ACD registers.
•
The ADC_CONFIG bit (bit 1): this bit indicates whether the data in the ACD register
corresponds to the loaded configuration (bit is set to 0) or to an old configuration (bit is
set to 1). A configuration is assumed to be loaded as soon as the update bit in the
ADC_CONTROL register is set.
shows the bit assignment of the ADC_STATUS register.
Table 379. ADC_CONTROL register bit description (ADC_CONTROL addresses, 0xE00C
2404 (ADC0), 0xE00C 3404 (ADC1), 0xE00C 4404 (ADC2)
* = reset value
Bit
Symbol
Access
Value
Description
31 to 3
reserved
R
-
Reserved; do not modify. Read as logic 0
2
UPDATE
R/W
1
Copy the configuration
0*
1
STOP
R/W
1
Stop ADC conversion
0*
0
START
R/W
1
Start ADC conversion
0*