8XC251SA, SB, SP, SQ USER’S MANUAL

5.3.4Data Transfer Instructions

Data transfer instructions copy data from one register or memory location to another. These in- structions include the move instructions (Table A-24 on page A-19) and the exchange, push, and pop instructions (Table A-25 on page A-22). Instructions that move only a single bit are listed with the other bit instructions in Table A-26 on page A-23.

MOV (Move) is the most versatile instruction, and its addressing modes are expanded in the MCS 251 architecture. MOV can transfer a byte, word, or dword between any two registers or between a register and any location in the address space.

The MOVX (Move External) instruction moves a byte from external memory to the accumulator or from the accumulator to memory. The external memory is in the region specified by DPXL, whose reset value is 01H. See section 3.3.2, “Dedicated Registers.”

The MOVC (Move Code) instruction moves a byte from code memory (region FF:) to the accu- mulator.

MOVS (Move with Sign Extension) and MOVZ (Move with Zero Extension) move the contents of an 8-bit register to the lower byte of a 16-bit register. The upper byte is filled with the sign bit (MOVS) or zeros (MOVZ). The MOVH (Move to High Word) instruction places 16-bit immedi- ate data into the high word of a dword register.

The XCH (Exchange) instruction interchanges the contents of the accumulator with a register or memory location. The XCHD (Exchange Digit) instruction interchanges the lower nibble of the accumulator with the lower nibble of a byte in on-chip RAM. XCHD is useful for BCD (binary coded decimal) operations.

The PUSH and POP instructions facilitate storing information (PUSH) and then retrieving it (POP) in reverse order. Push can push a byte, a word, or a dword onto the stack, using the imme- diate, direct, or register addressing modes. POP can pop a byte or a word from the stack to a reg- ister or to memory.

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Intel 8XC251SQ, 8XC251SA, 8XC251SP, 8XC251SB, Embedded Microcontroller manual Data Transfer Instructions
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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.
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