CHAPTER 2 PIN FUNCTIONS
User’s Manual U13850EJ4V0UM
63
(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 comprise the multiplexed address/data bus that is used for external access. At the address
timing (T1 state), these pins operate as AD0 to AD7 (22-bit address) output pins. At the data timing
(T2, TW, T3), they operate as the lower 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 can be specified in 1-bit units.
P50 to P57 can function as I/O port pins and as a time division address/data bus (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 in 1-bit units 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 AD
1
5 (Address/Data 8 to
1
5)
∙∙∙
3-state I/O
These comprise the multiplexed address/data bus that is used for external access. At the address
timing (T1 state), these pins operate as AD8 to AD15 (22-bit address) output pins. At the data timing
(T2, TW, T3), they operate as the higher 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. The higher 2 bits of port 6 are ignored when data is written to the port in 8-bit units. When data is
read from the port, 00 is read from these bits. Port/control mode can be selected for each 2 bits.
The I/O signal level uses the bus interface power supply pins BV
DD
and BV
SS
as reference.
(a) Port mode
P60 to P65 can be set in 1-bit units as input or output pins according to the contents of the port 6 mode
register (PM6).
(b) Control mode
P60 to P65 can be set as A16 to A21 according to the contents of the memory expansion register (MM).