
CHAPTER 2 PIN FUNCTIONS
45
(b) Control mode (external expansion mode)
P40 to P47 can be set as AD0 to AD7 according to the contents of the memory expansion register (MM).
(i)
AD0 to AD7 (Address/Data 0 to 7) ··· 3-state I/O
These are multiplexed address/data bus that is used for external access. Under address timing (T1
state), these pins operate as AD0 to AD7 (22-bit address) output pins. Under data timing (T2, TW, T3),
they operate as low-order 8-bit I/O bus pins for 16-bit data. The output changes in synchronization with
the rising edge of the clock in each state within the bus cycle. When the timing sets the bus cycle as
inactive, these pins go into a high-impedance state.
(6) P50 to P57 (Port 5) ··· 3-state I/O
Port 5 is an 8-bit I/O port in which input and output pins can be specified in 1-bit units.
P50 to P57 can function as I/O port pins and as a time division address/data buses (AD8 to AD15) when memory
is expanded externally.
The I/O signal level uses the bus interface power supply pins BV
DD
and BV
SS
as reference.
(a) Port mode
P50 to P57 can be set bit-wise as input or output pins according to the contents of the port 5 mode register
(PM5).
(b) Control mode (external expansion mode)
P50 to P57 can be set as AD8 to AD15 according to the contents of the memory expansion register (MM).
(i)
AD8 to AD15 (Address/Data 8 to 15) ··· 3-state I/O
These comprise the multiplexed address/data bus that is used for external access. Under address
timing (T1 state), these pins operate as AD8 to AD15 (22-bit address) output pins. Under data timing
(T2, TW, T3), they operate as high-order 8-bit I/O bus pins for 16-bit data. The output changes in
synchronization with the rising edge of the clock in each state within the bus cycle. When the timing
sets the bus cycle as inactive, these pins go into a high-impedance state.
(7) P60 to P65 (Port 6) ··· 3-state I/O
Port 6 is a 6-bit I/O port in which input and output pins can be specified in 1-bit units.
P60 to P65 can function as I/O port pins and as address buses (A16 to A21) when memory is expanded
externally. These pins can be set in 2 bit units to port mode or an external expansion mode.
Port/control mode can be selected for each bit.
The I/O signal level uses the bus interface power supply pins BV
DD
and BV
SS
as reference.