I/o instructions – NEC PD750008 User Manual

Page 314

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µPD750008 USER'S MANUAL

DI IExxx

Function: IExxx <– 0 xxx = N

5

, N

2-0

Resets an interrupt enable flag (IExxx) to 0 to disable an interrupt. (xxx = BT, CSI, T0, T1, W, 0, 1, 2, 4)

11.4.13 I/O Instructions

IN A,PORTn

Function: A <– PORTn n = N

3-0

: 0–8

Transfers the contents of the port specified by PORTn (n = 0-8) to the A register.

Caution Before this instruction can be executed, MBE = 0 or (MBE = 1, MBS = 15) must be set. A

number from 0 to 8 can be specified as n. Depending on I/O mode specification, output

latch data (in the output mode) or pin data (in the input mode) are transferred.

IN XA,PORTn

Function: A <– PORTn, X <– PORT

n+1

n = N

3-0

: 4, 6

Transfers the contents of the port specified by PORTn (n = 4 or 6) to the A register, then transfers the

contents of the next port to the X register.

Caution Only the number 4 or 6 can be specified as n. Before this instruction can be executed,

MBE = 0 or (MBE = 1, MBS = 15) must be set. Depending on I/O mode specification, output

latch data (in the output mode) or pin data (in the input mode) are transferred.

OUT PORTn, A

Function: PORTn <– A n = N

3-0

: 2–8

Transfers the contents of the A register to the output latch of the port specified by PORTn (n = 2–8).

Caution Before this instruction can be executed, MBE = 0 or (MBE = 1, MBS = 15) must be set.

A number from 2 to 8 can be specified as n.

OUT PORTn, XA

Function: PORTn <– A, PORT

n+1

<– X n = N

3-0

: 4, 6

Transfers the contents of the A register to the output latch of the port specified by PORTn (n = 4, 6), then

transfers the contents of the X register to the output latch of the next port.

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