ATmega325PA Atmel Corporation, ATmega325PA Datasheet - Page 243

• Manufacturer Part Number: ATmega325PA
• Manufacturer: Atmel Corporation

8285D–AVR–06/11
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P
When no alternate port function is present, the Input Data – ID – corresponds to the PINxn Reg-
ister value (but ID has no synchronizer), Output Data corresponds to the PORT Register, Output
Control corresponds to the Data Direction – DD Register, and the Pull-up Enable – PUExn – cor-
responds to logic expression PUD · DDxn · PORTxn.
Digital alternate port functions are connected outside the dotted box in
to make the scan chain read the actual pin value. For Analog function, there is a direct connec-
tion from the external pin to the analog circuit, and a scan chain is inserted on the interface
between the digital logic and the analog circuitry.
Figure 25-3. Boundary-scan Cell for Bi-directional Port Pin with Pull-up Function.
Pullup Enable (PUE)
Output Control (OC)
Output Data (OD)
Input Data (ID)
0
1
From Last Cell
0
1
0
1
0
1
ShiftDR
ClockDR
D
D
D
FF2
FF1
FF0
To Next Cell
Q
Q
Q
UpdateDR
D
G
D
G
D
G
LD2
LD1
LD0
Q
Q
Q
0
1
0
1
0
1
EXTEST
Figure 25-4 on page 244
Vcc
243