W742C81A データシートの表示（PDF） - Winbond

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W742C81A

4-BIT MICROCONTROLLER

Winbond 

Preliminary W742E81A/W742C81A

Bit 3, Bit 2, Bit 1, Bit 0 Data memory bank preselect bits:

0000 = Data bank 0 (000H - 07FH)

0001 = Data bank 1 (080H - 0FFH)

0010 = Data bank 2 (100H - 17FH)

0011 = Data bank 3 (180H - 1FFH)

0100 = Data bank 4 (200H - 27FH)

0101 = Data bank 5 (280H - 2FFH)

0110 = Data bank 6 (300H - 37FH)

0111 = Data bank 7 (380H - 3FFH)

1000 = Data bank 8 (400H - 47FH)

1001 = Data bank 9 (480H - 4FFH)

1010 = Data bank A (500H - 57FH)

1011 = Data bank B (580H - 5FFH)

1100 = Data bank C (600H - 67FH)

1101 = Data bank D (680H - 6FFH)

1110 = Data bank E (700H - 77FH)

1111 = Data bank F (780H - 7FFH)

6.5 Accumulator (ACC)

The accumulator (ACC) is a 4-bit register used to hold results from the ALU and transfer data

between the memory, I/O ports, and registers.

6.6 Arithmetic and Logic Unit (ALU)

This is a circuit which performs arithmetic and logic operations. The ALU provides the following

functions:

• Logic operations: ANL, XRL, ORL

• Branch decisions: JB0, JB1, JB2, JB3, JNZ, JZ, JC, JNC, DSKZ, DSKNZ, SKB0, SKB1, SKB2,

SKB3

• Shift operations: SHRC, RRC, SHLC, RLC

• Binary additions/subtractions: ADC, SBC, ADD, SUB, ADU, DEC, INC

After any of the above instructions are executed, the status of the carry flag (CF) and zero flag (ZF) is

stored in the internal registers. CF can be read out by executing MOV R, CF.

6.7 Main-Oscillator

The W742E81A/W742C81A provides a crystal or RC oscillation circuit to generate the system clock

through external connections. If a crystal oscillator is used, The 3.58 MHz or 400KHz crystal must

be connected to XIN1 and XOUT1, and a capacitor must be connected to XIN1 and VSS if an accurate

frequency is needed.

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Publication Release Date: April 2000

Revision A1

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