ATMEGA325-16AJ ATMEL [ATMEL Corporation], ATMEGA325-16AJ Datasheet - Page 225

• Manufacturer Part Number: ATMEGA325-16AJ
• Description: 8-bit Microcontroller with In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Scanning the ADC
2570A–AVR–09/04
Table 94. Boundary-scan Signals for the Analog Comparator
Figure 107 shows a block diagram of the ADC with all relevant control and observe sig-
nals. The Boundary-scan cell from Figure 103 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 107. Analog to Digital Converter
The signals are described briefly in Table 95.
NEGSEL_2
NEGSEL_1
NEGSEL_0
MUXEN_7
MUXEN_6
MUXEN_5
MUXEN_4
MUXEN_3
MUXEN_2
MUXEN_1
MUXEN_0
Signal
Name
AC_IDLE
ACO
ACME
ACBG
EXTCH
ADC_7
ADC_6
ADC_5
ADC_4
ADC_3
ADC_2
ADC_1
ADC_0
ADC_2
ADC_1
ADC_0
Direction as
Seen from the
Comparator
input
output
input
input
SCTEST
AMPEN
ACLK
ST
To Comparator
+
-
1x
Description
Turns off Analog
Comparator when
true
Analog
Comparator Output
Uses output signal
from ADC mux
when true
Bandgap
Reference enable
ADCBGEN
VCCREN
IREFEN
AREF
ATmega325/3250/645/6450
PASSEN
ACTEN
1.22V
GNDEN
ref
1.11V
ref
Recommended
Input when Not
in Use
1
Will become
input to µC code
being executed
0
0
PRECH
DAC_9..0
ADCEN
HOLD
PRECH
AREF
10-bit DAC
Output Values when
Recommended
Inputs are Used
Depends upon µC
code being executed
0
Depends upon µC
code being executed
Depends upon µC
code being executed
AREF
+
-
DACOUT
COMP
COMP
225