Motorola MC68VZ328 - Manual (Page 181)

Programming Model
I/O Ports 10-11
PBPUEN Port B Pull-up Enable Register 0x(FF)FFF40A
10.4.2.5 Port B Select Register
The Port B select register (PBSEL) determines if a bit position in the data register (PBDATA) is assigned
as a general purpose I/O or to a dedicated I/O function. The settings for the bit positions are shown in
Table 10-11.
PBSEL Port B Select Register 0x(FF)FFF40B
10.4.3 Port C Registers
Port C is composed of the following 8-bit general-purpose I/O registers:
• Port C direction register (PCDIR)
• Port C data register (PCDATA)
• Port C pull-down enable register (PCPDEN)
• Port C select register (PCSEL)
Each signal in the PCDATA register connects to an external pin. As with the other ports, each bit on Port C
is individually configured.
BIT 7 6 5 4 3 2 1 BIT 0
PU7 PU6 PU5 PU4 PU3 PU2 PU1 PU0
TYPE rw rw rw rw rw rw rw rw
RESET
1 1 1 1 1 1 1 1
0xFF
Table 10-10. Port B Pull-up Enable Register Description
Name Description Setting
PUx
Bits 7–0 Pull-up—These bits enable the pull-up resis-
tors on the port. 0 = Pull-up resistors are disabled
1 = Pull-up resistors are enabled
BIT 7 6 5 4 3 2 1 BIT 0
SEL7 SEL6 SEL5 SEL4 SEL3 SEL2 SEL1 SEL0
TYPE rw rw rw rw rw rw rw rw
RESET
1 1 1 1 1 1 1 1
0xFF
Table 10-11. Port B Select Register Description
Name Description Setting
SELx
Bits 7–0 Select —These bits select whether the internal chip
function or I/O port signals are connected to the
pins. 0 = The dedicated function pins are connected.
1 = The I/O port function pins are connected.