Motorola MC68VZ328 - Manual (Page 209)

Programming Model
I/O Ports 10-39
10.4.11.3 Port M Dedicated I/O Functions
The six PMDATA lines are multiplexed with the dedicated I/O signals whose assignments are shown in
Table 10-53.
All of the dedicated I/O functions are involved in the operation of the DRAM controller. See Chapter 7,
“DRAM Controller,” for more details.
10.4.11.4 Port M Pull-up/Pull-down Enable Register
The pull-up/pull-down enable register (PMPUEN) controls the pull-up and pull-down resistors for each
line in Port M. The settings for the PMPUEN register bit positions are shown in Table 10-54.
PMPUEN Port M Pull-up/Pull-down Enable Register 0x(FF)FFF44A
Table 10-53. Port M Dedicated I/O Function Assignments
Bit GPIO Function Dedicated I/O Function
0 Data bit 0 SDCLK
1 Data bit 1 SDCE
2 Data bit 2 DQMH
3 Data bit 3 DQML
4 Data bit 4 SDA10
5 Data bit 5 DMOE
6
7
BIT 7 6 5 4 3 2 1 BIT 0
PU5 PD4 PD3 PD2 PD1 PD0
TYPE rw rw rw rw rw rw
RESET
0 0 1 1 1 1 1 1
0x3F
Table 10-54. Port M Pull-up/Pull-down Enable Register Description
Name Description Setting
Reserved
Bits
7–6
Reserved These bits are reserved and should be set to 0.
PUx
Bits 5–0 Pull-up/Pull-down Enable—These bits enable
the pull-up and pull-down resistors on the port. 0 = Pull-up and pull-down resistors are disabled
1 = Pull-up and pull-down resistors are enabled