266
2467S–AVR–07/09
ATmega128
ATmega128
Boundary-scan
Order
shows the Scan order between TDI and TDO when the Boundary-scan Chain is
selected as data path. Bit 0 is the LSB; the first bit scanned in, and the first bit scanned out. The
scan order follows the pin-out order as far as possible. Therefore, the bits of Port A is scanned in
the opposite bit order of the other ports. Exceptions from the rules are the Scan chains for the
analog circuits, which constitute the most significant bits of the scan chain regardless of which
physical pin they are connected to. In
, PXn. Data corresponds to FF0, PXn. Control
corresponds to FF1, and PXn. Pullup_enable corresponds to FF2. Bit 2, 3, 4, and 5 of Port C is
not in the scan chain, since these pins constitute the TAP pins when the JTAG is enabled.
Table 106.
ATmega128 Boundary-scan Order
Bit Number
Signal Name
Module
204
AC_IDLE
Comparator
203
ACO
202
ACME
201
AINBG
200
COMP
ADC
199
PRIVATE_SIGNAL1
198
ACLK
197
ACTEN
196
PRIVATE_SIGNAL1
195
ADCBGEN
194
ADCEN
193
AMPEN
192
DAC_9
191
DAC_8
190
DAC_7
189
DAC_6
188
DAC_5
187
DAC_4
186
DAC_3
185
DAC_2
184
DAC_1
183
DAC_0
182
EXTCH
181
G10
180
G20
179
GNDEN
178
HOLD
177
IREFEN
176
MUXEN_7