Programming Model
I/O Ports
10-29
PGDATA
Port G Data Register
0x(FF)FFF431
Port G is multiplexed with address line A0 and several dedicated I/O functions. These pins can be
programmed as GPIO when the address bus and the dedicated I/O signals are not in use.
All of the bits control or report the data on the pins while the associated SELx bits
are high. While the
DIRx bits are high (output), the Dx bits control the pins. While the DIRx bits are low (input), the Dx bits
report the signal driving the pins. The Dx bits can be written at any time. Bits that are configured as inputs
will accept the data, but the data written to each cannot be accessed until the corresponding pin is
configured as an output. The actual value on the pin is reported when these bits are read, regardless of
whether they are configured as input or output. See Table 10-36 on page 10-28 for information about
setting the bits in the PGDIR register.
10.4.8.3
Port G Dedicated I/O Functions
The six PGDATA lines are multiplexed with the dedicated I/O signals whose assignments are shown in
Table 10-38.
BIT 7
6
5
4
3
2
1
BIT 0
D5
D4
D3
D2
D1
D0
TYPE
rw
rw
rw
rw
rw
rw
RESET
0
0
1
1
1
1
1
1
0x3F*
*Actual bit value depends on external circuits connected to pin.
Table 10-37. Port G Data Register Description
Name Description
Setting
Reserved
Bits
7–6
Reserved
These bits are reserved and should be set to 0.
Dx
Bits 5–0
Data—These bits reflect the
status of the I/O signal in an
8-bit system.
0 = Drives the output signal low when DIRx is set to 1 or the external
signal is low when DIRx is set to 0
1 = Drives the output signal high when DIRx is set to 1 or the external
signal is high when DIRx is set to 0
Table 10-38. Port G Dedicated I/O Function Assignments
Bit
GPIO Function
Dedicated I/O Function
0
Data bit 0
BUSW/DTACK
1
Data bit 1
A0
2
Data bit 2
EMUIRQ
3
Data bit 3
HIZ/P/D
4
Data bit 4
EMUCS
5
Data bit 5
EMUBRK
6
7
Summary of Contents for MC68VZ328
Page 1: ...MC68VZ328UM D Rev 0 02 2000 MC68VZ328 Integrated Processor User s Manual ...
Page 14: ...xiv MC68VZ328 User s Manual ...
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Page 26: ...xxvi MC68VZ328 User s Manual ...
Page 42: ...1 12 MC68VZ328 User s Manual Modules of the MC68VZ328 ...
Page 54: ...2 12 MC68VZ328 User s Manual In Circuit Emulation ICE Signals ...
Page 68: ...3 14 MC68VZ328 User s Manual Programmer s Memory Map ...
Page 110: ...6 22 MC68VZ328 User s Manual Programming Model ...