263
2467S–AVR–07/09
ATmega128
GNDEN
Input
Ground the negative
input to comparator
when true
0
0
HOLD
Input
Sample & Hold signal.
Sample analog signal
when low. Hold signal
when high. If gain
stages are used, this
signal must go active
when ACLK is high.
1
1
IREFEN
Input
Enables Band-gap
reference as AREF
signal to DAC
0
0
MUXEN_7
Input
Input Mux bit 7
0
0
MUXEN_6
Input
Input Mux bit 6
0
0
MUXEN_5
Input
Input Mux bit 5
0
0
MUXEN_4
Input
Input Mux bit 4
0
0
MUXEN_3
Input
Input Mux bit 3
0
0
MUXEN_2
Input
Input Mux bit 2
0
0
MUXEN_1
Input
Input Mux bit 1
0
0
MUXEN_0
Input
Input Mux bit 0
1
1
NEGSEL_2
Input
Input Mux for negative
input for differential
signal, bit 2
0
0
NEGSEL_1
Input
Input Mux for negative
input for differential
signal, bit 1
0
0
NEGSEL_0
Input
Input Mux for negative
input for differential
signal, bit 0
0
0
PASSEN
Input
Enable pass-gate of
gain stages.
1
1
PRECH
Input
Precharge output latch
of comparator. (Active
low)
1
1
Table 104.
Boundary-scan Signals for the ADC (Continued)
Signal
Name
Direction
as Seen
from the
ADC
Description
Recommen-
ded Input
when not
in Use
Output Values when
Recommended Inputs
are Used, and CPU is
not Using the ADC
