305
7679H–CAN–08/08
AT90CAN32/64/128
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 connection from the
external pin to the analog circuit, and a scan chain is inserted on the interface between the digi-
tal logic and the analog circuitry.
Figure 23-3.
Boundary-scan Cell for Bi-directional Port Pin with Pull-up Function.
D
Q
D
Q
G
0
1
0
1
D
Q
D
Q
G
0
1
0
1
0
1
0
1
D
Q
D
Q
G
0
1
Port Pin (PXn)
Vcc
EXTEST
To Next Cell
ShiftDR
Output Control (OC)
Pullup Enable (PUE)
Output Data (OD)
Input Data (ID)
From Last Cell
UpdateDR
ClockDR
FF2
LD2
FF1
LD1
LD0
FF0
