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

Page 354 Page 356
Page 355
Image 355
Intel 8XC251SA Nop, Function Description Flags, Bytes States Encoding Hex Code Operation, NOP Setb P2.7, ORL dest src
Page 354 Page 356

Embedded Microcontroller, 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB specifications

The Intel 8XC251 series of embedded microcontrollers is a family of versatile and powerful devices, designed to meet the demands of a wide range of applications. With models such as the 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP, this series offers unique features while maintaining a high level of performance and reliability.

At the heart of the 8XC251 microcontrollers is the 8051 architecture, which provides a 16-bit processor capable of executing complex instructions efficiently. This architecture not only allows for a rich instruction set but also facilitates programming in assembly language and higher-level languages like C, which are essential for developing sophisticated embedded systems.

One of the significant features of the 8XC251 family is its integrated peripherals, including timer/counters, serial communication interfaces, and interrupt systems. These peripherals enable developers to implement timing functions, data communication, and real-time processing, all of which are crucial in modern embedded applications. The 8XC251SB and 8XC251SQ models, for instance, come equipped with multiple I/O ports that allow for interfacing with other devices and systems, enhancing their functionality in various environments.

The memory architecture of the 8XC251 devices is noteworthy, featuring on-chip ROM, RAM, and EEPROM. The on-chip memory allows for fast access times, which is essential for executing programs efficiently. Moreover, the EEPROM serves as non-volatile memory, enabling the storage of configuration settings and important data that must be retained even when power is lost.

In terms of operating voltage, the 8XC251 devices are designed to operate in a wide range, typically between 4.0V and 6.0V. This flexibility makes them suitable for battery-powered applications, where energy efficiency is critical. The power management features, including reduced power modes, further enhance their suitability for portable devices.

Lastly, the 8XC251 series is supported by a wide range of development tools and resources, allowing engineers and developers to streamline the development process. This support, combined with the microcontrollers' robust features, makes the Intel 8XC251 family a reliable choice for various embedded applications, such as industrial automation, automotive systems, and consumer electronics.

Overall, the Intel 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP deliver high performance, versatility, and ease of use, making them a preferred choice for embedded system designers looking to develop efficient and effective solutions.
Top Page Image Contents