
CHAPTER 2 PIN FUNCTIONS
50
(b) Control mode
(i)
A1 to A4 (Address 1 to 4) ··· output
These comprise the address bus that is used for external access. These pins operate as the low-order
4-bit address output pins within a 22-bit address. The output changes in synchronization with the
rising edge of the clock in the T1 state of the bus cycle. When the timing sets the bus cycle as
inactive, the previous bus cycle’s address is retained.
(ii)
WAIT (Wait) ··· input
This is an input pin for the control signal used to insert waits into the bus cycle. This pin is sampled at
the falling edge of the clock during the T2 or TW state of the bus cycle.
ON/OFF switching of the wait function is performed by the port alternate function control register
(PAC).
Caution
When using the wait function, set BV
DD
to the same potential as EV
DD
.
(12) RESET (Reset) ··· input
RESET input is asynchronous input for a signal that has a constant low level width regardless of the operating
clock’s status. When this signal is input, a system reset is executed as the first priority ahead of all other
operations.
In addition to being used for ordinary initialization/start operations, this pin can also be used to cancel a standby
mode (HALT, IDLE, or STOP mode).
(13) REGC (Regulator Control) ... input
This pin is used to connect the regulator-use capacitor.
(14) X1 and X2 (Crystal)
These pins are used to connect the resonator that generates the system clock.
(15) XT1, XT2 (Crystal for Sub-clock)
These pins are used to connect the resonator that generates the subclock.
(16) AV
DD
(Analog V
DD
)
This is the analog power supply pin for the A/D converter and alternate-function ports.
(17) AV
SS
(Analog V
SS
)
This is the ground pin for the A/D converter and alternate-function ports.
(18) AV
REF
(Analog Reference Voltage) … input
This is the reference voltage supply pin for the A/D converter.
(19) BV
DD
(Power Supply for Bus Interface)
This is the positive power supply pin for the bus interface and alternate-function ports.
(20) BV
SS
(Ground for Bus Interface)
This is the ground pin for the bus interface.