CHAPTER 2 PIN FUNCTIONS
User’s Manual U13850EJ4V0UM
67
(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 lower 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 Because the supply voltage to the I/O buffer of the WAIT pin is EV
DD
, if the voltage of
EV
DD
and that of BV
DD
differ, use EV
DD
as the voltage of the external wait signal,
instead of BV
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) CLKOUT (Clock Out) … output
This pin outputs the bus clock generated internally.
(15) X1 and X2 (Crystal)
These pins are used to connect the resonator that generates the system clock.
(16) XT1, XT2 (Crystal for Sub Clock)
These pins are used to connect the resonator that generates the sub clock.
(17) AV
DD
(Analog V
DD
)
This is the analog power supply pin for the A/D converter and alternate-function ports.
(18) AV
SS
(Analog V
SS
)
This is the ground pin for the A/D converter and alternate-function ports.
(19) AV
REF
(Analog Reference Voltage) … input
This is the reference voltage supply pin for the A/D converter.
(20) BV
DD
(Power Supply for Bus Interface)
This is the positive power supply pin for the bus interface and alternate-function ports.
Содержание MPD703030A
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