AT90CAN128_14 Datasheet, PDF (305/428 Pages) ATMEL Corporation – Non volatile Program and Data Memories

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 Figure 23-4 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.
ShiftDR
To Next Cell
EXTEST
Vcc
Pullup Enable (PUE)
0
FF2
LD2
1
0
DQ
DQ
1
G
Output Control (OC)
FF1
LD1
0
0
DQ
DQ
1
1
G
Output Data (OD)
0
0
1
1
Input Data (ID)
FF0
DQ
LD0
0
DQ
1
G
From Last Cell ClockDR
UpdateDR
7679H–CAN–08/08
305