Epson E0C6001 Technical Manual page 108

Cmos 4-bit single chip microcomputer

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Fig. 3.4.3

Control of the I/O port (output)

• Loading contents of B register into P00–P03

Label

Mnemonic/operand

Y,0FCH

MY,0001B

Y,0F6H

MY,B

As shown in Figure 3.4.3, the four instruction steps above

load the data of the B register into the I/O ports.

B register

The output data can be taken from the A register, MX, or

immediate data instead of the B register.

Bit-unit operation for the I/O port is identical to that for the

input ports (K00–K03) or output ports (R00, R01).

CHAPTER 3: PERIPHERAL CIRCUITS (I/O Port)

Comment

;

Set the address of input/output

;

port control register

;

Set port as output port

;

Set the address of port

P00–P03 ← B register

;

Data register

P00

P01

P02

P03

II-27

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