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CHAPTER 2 PIN FUNCTIONS
(i)
AD0 to AD7 (Address/Data 0 to 7) ... 3-state I/O
These pins constitute a multiplexed address/data bus when the external memory is accessed. They
function as the A0 to A7 output pins of a 20-bit address in the address timing (T1 state), and as the
lower 8-bit data I/O bus pins of 16-bit data in the data timing (T2, TW, T3).
The output status of these pins changes in synchronization with the rising edge of the clock in each
state of the bus cycle. AD0 to AD7 go into a high-impedance state in the idle state (TI).
(6) P50 to P57 (Port 5) ... 3-state I/O
These pins constitute an 8-bit I/O port, port 5. They also form a portion of the address/data bus connected
to external memory.
P50 to P57 function not only as I/O port pins but also as multiplexed address/data bus pins (AD8 to AD15)
in the control mode (external expansion mode) when an external memory is connected.
Each bit of this port can be set in the port or control mode in 1-bit units by using mode specification pin (MODE)
and memory expansion mode register (MM).
(a) Port mode
P50 to P57 can be set in the input or output port mode in 1-bit units by using port 5 mode register (PM5).
(b) Control mode (External Expansion Mode)
P50 to P57 can be specified as AD8 to AD15 by using the MODE pin and MM register.
(i)
AD8 to AD15 (Address/Data 8 to 15) ... 3-state I/O
These pins constitute a multiplexed address/data bus when the external memory is accessed. They
function as the A8 to A15 output pins of a 20-bit address in the address timing (T1 state), and as
the higher 8-bit data I/O bus pins of 16-bit data in the data timing (T2, TW, T3).
The output status of these pins changes in synchronization with the rising of the clock in each state
of the bus cycle. AD8 to AD15 go into a high-impedance state in the idle state (TI).
(7) P60 to P63 (Port 6) ... 3-state I/O
These pins constitute an 4-bit I/O port, port 6. They also form a portion of the address bus connected to external
memory.
P60 to P63 function not only as I/O port pins but also as address bus pins (A16 to A19) in the control mode
(external expansion mode) when an external memory is connected. This port can be set in the port or control
mode in 2-bit units by using mode specification pin (MODE) and memory expansion mode register (MM).
(a) Port mode
P60 to P63 can be set in the input or output port mode in 1-bit units by using port 6 mode register (PM6).
(b) Control mode (External Expansion Mode)
P60 to P63 can be specified as A16 to A19 by using the MODE pin and MM register.
(i)
A16 to A19 (Address 16 to 19) ... output
These pins constitute the higher 4 bits of a 20-bit address bus when the external memory is accessed.
The output status of these pins changes in synchronization with the rising edge of the clock in the
T1 state. During the idle state (TI), the address of the bus cycle immediately before entering the
idle state is retained.