CHAPTER 2 PIN FUNCTIONS
User’s Manual U13850EJ6V0UD
90
(11) P110 to P113 (Port 11) ··· 3-state I/O
P110 to P113 constitute a 4-bit I/O port that can be set to input or output in 1-bit units.
P110 to P113 can also function as an address bus (A1 to A4) when memory is expanded externally, signal
(WAIT) that inserts waits into the bus cycle and a control.
(a) Port function
P110 to P113 can be set to input or output in 1-bit units using the port 11 mode register (PM11).
(b) Alternate functions
(i)
A1 to A4 (Address bus 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
The RESET pin is an asynchronous input and inputs a signal that has a constant low level width regardless of
the status of the operating clock. 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 release a
standby mode (HALT, IDLE, or STOP mode).
(13) REGC (Regulator control) ... input
This pin is used to connect the capacitor for the regulator.
(14) CLKOUT (Clock out) … output
This pin outputs the bus clock generated internally.
(15) X1, X2 (Crystal)
These pins are used to connect the resonator that generates the main clock.
(16) XT1, XT2 (Crystal for subclock)
These pins are used to connect the resonator that generates the subclock.
(17) AV
DD
(Analog V
DD
)
This is the analog positive power supply pin for the A/D converter or alternate-function port.
Содержание V850/SB1
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