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CHAPTER 6 PORT FUNCTIONS
6.2.8 Port 6
This is an 8-bit I/O port with output latch. P60-P67 pins can be specified in the input or output mode in 1-bit units
by using the port mode register 6 (PM6).
This port can be connected with pull-up resistors as described in the following table. The number of bits in units
of which the pull-up resistor can be connected differs depending on whether the high-order or low-order 4 bits of the
port are involved and also depending on whether the product is ROM or PROM model.
Table 6-4. Pull-Up Resistors in Port 6
High-order 4 Bits (P64-P67 pins)
Low-order 4 Bits (P60-P63 pins)
Mask ROM model
Internal pull-up resistor can be connected in
4-bit units by PUO6
Internal pull-up resistor can be connected in 1-bit
units by mask option
PROM model
Internal pull-up resistor is not connected
PUO6: Bit 6 of pull-up resistor option register (PUO)
P60-P63 pins can directly drive an LED.
P64-P67 pins are also used to output control signals in the external memory extension mode.
This port is set in the input mode when the RESET signal is input.
Figures 6-14 and 6-15 show the block diagrams of port 6.
Cautions 1. P66 can be used as an I/O port pins when no external wait state is used in the external memory
extension mode.
2. The value of the low-level input leakage current flowing through P60 through P63 differs
depending on the following conditions:
[Mask ROM model]
When pull-up resistor is connected: always –3
μ
A (MAX.)
When pull-up resistor is not connected
· For duration of 3 clocks (without wait) when a read instruction
is executed to port 6 (P6) or port mode register 6 (PM6)
· Others
[PROM model]
For duration of 3 clocks (without wait) when a read instruction
is executed to port 6 (P6) or port mode register 6 (PM6)
Others
: –200
μ
A (MAX.)
: –3
μ
A (MAX.)
: –200
μ
A (MAX.)
: –3
μ
A (MAX.)