Intel 8XC251SA manual Nop, Function Description Flags, Bytes States Encoding Hex Code Operation

INSTRUCTION SET REFERENCE

NOP

Function:

Description:

Flags:

Example:

Bytes:

States:

[Encoding]

Hex Code in:

Operation:

No operation

Execution continues at the following instruction. Affects the PC register only.

CY	AC	OV	N	Z
—	—	—	—	—

You want to produce a low-going output pulse on bit 7 of Port 2 that lasts exactly 11 states. A simple CLR-SETB sequence generates an eight-state pulse. (Each instruction requires four states to write to a port SFR.) You can insert three additional states (if no interrupts are enabled) with the following instruction sequence:

CLR P2.7

NOP

NOP

NOP

SETB P2.7

Binary Mode Source Mode

1	1
1	1
0 0 0 0	0 0 0 0

Binary Mode = [Encoding]

Source Mode = [Encoding]

NOP

(PC) ← (PC) + 1

ORL <dest> <src>

Function: Logical-OR for byte variables

Description: Performs the bitwise logical-OR operation (V) between the specified variables, storing the results in the destination operand.

The destination operand can be a register, an accumulator or direct address.

The two operands allow twelve addressing mode combinations. When the destination is the accumulator, the source can be register, direct, register-indirect, or immediate addressing; when the destination is a direct address, the source can be the accumulator or immediate data. When the destination is register the source can be register, immediate, direct and indirect addressing.

Note: When this instruction is used to modify an output port, the value used as the original port data is read from the output data latch, not the input pins.

Flags:

CY	AC	OV	N	Z
—	—	—	✓	✓

A-103