Datasheet

315
ATmega640/1280/1281/2560/2561
2549K–AVR–01/07
ATmega640/1280/1281/25
60/2561 Boundary-scan
Order
Table 132 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 and Port K is scanned in the opposite bit order of the other ports. Excep-
tions 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 con-
nected to. In Figure 132, PXn. Data corresponds to FF0, PXn. Control corresponds to
FF1, PXn. Bit 4, 5, 6 and 7 of Port F is not in the scan chain, since these pins constitute
the TAP pins when the JTAG is enabled.
Boundary-scan
Description Language
Files
Boundary-scan Description Language (BSDL) files describe Boundary-scan capable
devices in a standard format used by automated test-generation software. The order
and function of bits in the Boundary-scan Data Register are included in this description.
BSDL files are available for ATmega1281/2561 and ATmega640/1280/2560.
Table 132. ATmega640/1280/2560 Boundary-scan Order
Bit Number Signal Name Module
164 PG5.Data Port G
163 PG5.Control
162 PE0.Data Port E
161 PE0.Control
160 PE1.Data
159 PE1.Control
158 PE2.Data
157 PE2.Control
156 PE3.Data
155 PE3.Control
154 PE4.Data
153 PE4.Control
152 PE5.Data
151 PE5.Control
150 PE6.Data
149 PE6.Control
148 PE7.Data
147 PE7.Control
146 PH0.Data Port H
145 PH0.Control
144 PH1.Data
143 PH1.Control
142 PH2.Data
141 PH2.Control