Motorola MC68VZ328 - Manual (Page 185)

Programming Model
I/O Ports 10-15
10.4.4 Port D Operation
Port D has the same functionality as other GPIO ports, except that it also has interrupt capabilities. It
should be used as either a general-purpose, interrupt-generating port or as a keyboard input port.
Figure 10-3 illustrates how this type of port operates.
Figure 10-3. Interrupt Port Operation
Port D generates nine interrupt signals. Eight of these interrupts are generated by the bits of each port. One
bit is the logical OR result of all eight bits, which is applied to the MC68VZ328 interrupt controller as a
level 4 keyboard interrupt (KB) in the interrupt status register. See Section 9.6.4, “Interrupt Status
Register,” on page 9-12 for more details.
Pad
Data Register
Pull-up Enable Register
Pad
Buffer
Edge
Detect Polarity Register
Interrupt Request Edge Register
Interrupt Request Enable Register
Bit IRQ
Keyboard Interrupt
0
SEL
1
Direction Register
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•
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