INSTRUCTION SET REFERENCE

SRL WRj

Binary Mode Source Mode

Bytes:

States:

[Encoding]

Hex Code in:

Operation:

32

21

0 0 0 1

1 1 1 0

 

 

Binary Mode = [A5][Encoding] Source Mode = [Encoding]

SRL

(WRj).15 0

(WRj).b (WRj).b+1 CY(WRj).0

t t t t

0 1 0 0

SUB <dest>,<src>

Function: Subtract

Description: Subtracts the specified variable from the destination operand, leaving the result in the destination operand. SUB sets the CY (borrow) flag if a borrow is needed for bit 7. Otherwise, CY is clear.

When subtracting signed integers, the OV flag indicates a negative number produced when a negative value is subtracted from a positive value, or a positive result when a positive number is subtracted from a negative number.

Bit 7 in this description refers to the most significant byte of the operand (8, 16, or 32 bit).

The source operand allows four addressing modes: immediate, indirect, register and direct.

Flags:

CY

AC

OV

N

Z

 

 

 

 

 

 

 

 

 

 

†For word and dword subtractions, AC is not affected.

Example: Register 1 contains 0C9H (11001001B) and register 0 contains 54H (01010100B). After executing the instruction

SUB R1,R0

register 1 contains 75H (01110101B), the CY and AC flags are clear, and the OV flag is set.

Variations

SUB Rmd,Rms

 

Binary Mode

Source Mode

Bytes:

3

2

States:

2

1

[Encoding]

1 0 0 1

1 1 0 0

 

 

s s s s

S S S S

 

 

A-123

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Intel 8XC251SA, 8XC251SP, 8XC251SQ, 8XC251SB SUB dest,src Function Subtract, SUB R1,R0, Variations SUB Rmd,Rms Binary Mode

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.