Datasheet

257
ATmega169A/PA/329A/PA/649A/P/3290A/PA/6490A/P [DATASHEET]
8284E–AVR–02/2013
26.6 Atmel ATmega169A/169PA/329A/329PA/3290A/3290PA/649A/649P/6490A/6490P
Boundary-scan order
Table 26-7 on page 263 and Table 26-8 on page 270 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 Figure 26-2 on
page 249, PXn. Data corresponds to FF0, PXn. Control corresponds to FF1, and PXn. Pull-up_enable corresponds
to FF2. 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...
Table 26-6. Atmel ATmega169A/169PA Boundary-scan order.
Bit number Signal name Module
197 AC_IDLE
Comparator
196 ACO
195 ACME
194 AINBG