Motorola MC68VZ328 - Manual (Page 178)

10-8 MC68VZ328 User’s Manual
Programming Model
10.4.1.3 Port A Pull-up Enable Register
The Port A pull-up enable register (PAPUEN) controls the pull-up resistors for each line in Port A. The
settings for the bit positions are shown in Table 10-6.
PAPUEN Port A Pull-up Enable Register 0x(FF)FFF402
10.4.2 Port B Registers
Port B is made up of the following 8-bit general-purpose I/O registers:
• Port B direction register (PBDIR)
• Port B data register (PBDATA)
• Port B pull-up enable register (PBPUEN)
• Port B select register (PBSEL)
Each signal line connects to an external pin. Each bit on Port B is individually configured.
10.4.2.1 Port B Direction Register
The Port B direction register controls the direction (input or output) of the line associated with the
PBDATA bit position. When the data bit is assigned to a dedicated I/O function, the direction bits are
ignored. The settings for the bit positions are shown in Table 10-7 on page 10-9.
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 10-6. Port A Pull-up Enable Register Description
Name Description Setting
PUx
Bits 7–0 Pull-up—These bits enable the pull-up resistors on
the port. 0 = Pull-up resistors are disabled
1 = Pull-up resistors are enabled