
CHAPTER 2 PIN FUNCTIONS
Preliminary User’s Manual U16541EJ1V0UM
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(iv) WAIT (wait) … Input
This is a control signal input pin that inserts data wait states in the bus cycle. Data can be input to
this pin asynchronous to the CLKOUT signal. In the multiplexed mode, this pin is sampled at the
falling edge of the CLKOUT signal in the T2 and TW states of the bus cycle. In the separate mode, it
is sampled at the rising edge of the CLKOUT signal immediately after the T1 and TW states of the
bus cycle. A wait state may not be inserted if the setup/hold time of the sampling timing is not
satisfied.
On/off switching of the wait function is performed using port mode control register CM (PMCCM).
(9) PCT0, PCT1, PCT4, PCT6 (port CT) … 3-state I/O
PCT0, PCT1, PCT4, and PCT6 function as a 4-bit I/O port for which input and output can be set in 1-bit units.
In addition to I/O pins, these pins can also be used as control signal output pins for external memory
expansion in the control mode.
(a) Port mode
PCT0, PCT1, PCT4, and PCT6 can be set to input or output in 1-bit units using port mode register CT
(PMCT).
(b) Control mode
(i)
WR0 (lower byte write strobe) … Output
This is the write strobe signal output pin for the lower data of the external 16-bit data bus.
(ii)
WR1 (upper byte write strobe) … Output
This is the write strobe signal output pin for the higher data of the external 16-bit data bus.
(iii) RD (read strobe) … Output
This is the read strobe signal output pin for the external 16-bit data bus.
(iv) ASTB (address strobe) … Output
This is the output pin for the latch strobe signal for the external address bus. Output becomes low
level in synchronization with the falling edge of the clock during the T1 state of the bus cycle, and
becomes high level in synchronization with the falling edge of the clock during the T3 state of the bus
cycle. Output becomes high level when the bus cycle is inactive.
(10) PDH0 to PDH5 (port DH) … 3-state I/O
PDH0 to PDH5 function as a 6-bit I/O port for which input and output can be set in 1-bit units.
In addition to I/O port pins, these pins can also be used as an address bus during external memory expansion
in the control mode.
(a) Port mode
PDH0 to PDH5 can be set to input or output in 1-bit units using port mode register DH (PMDH).