Datasheet

268
8018P–AVR–08/10
ATmega169P
25.5.5 Scanning the ADC
Figure 25-9 shows a block diagram of the ADC with all relevant control and observe signals. The
Boundary-scan cell from Figure 25-5 on page 265 is attached to each of these signals. The ADC
need not be used for pure connectivity testing, since all analog inputs are shared with a digital
port pin as well.
Figure 25-9. Analog to Digital Converter.
The signals are described briefly in Table 25-3 on page 269.
10-bit DAC +
-
AREF
PRECH
DACOUT
COMP
MUXEN_7
ADC_7
MUXEN_6
ADC_6
MUXEN_5
ADC_5
MUXEN_4
ADC_4
MUXEN_3
ADC_3
MUXEN_2
ADC_2
MUXEN_1
ADC_1
MUXEN_0
ADC_0
NEGSEL_2
ADC_2
NEGSEL_1
ADC_1
NEGSEL_0
ADC_0
EXTCH
+
-
1x
ST
ACLK
AMPEN
1.11V
ref
IREFEN
AREF
VCCREN
DAC_9..0
ADCEN
HOLD
PRECH
GNDEN
PASSEN
COMP
SCTEST
ADCBGEN
To Comparator
1.22V
ref
ACTEN
AREF