Manuals / Intel / Computer Equipment / Computer Hardware

Intel 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB, Embedded Microcontroller MCS 251 Microcontroller Core

Models: Embedded Microcontroller 8XC251SP 8XC251SA 8XC251SQ 8XC251SB

1 458
Download 458 pages 25.38 Kb
Page 36
Image 36

8XC251SA, SB, SP, SQ USER’S MANUAL

The 8XC251Sx has two power-saving modes. In idle mode, the CPU clock is stopped, while clocks to the peripherals continue to run. In powerdown mode, the on-chip oscillator is stopped, and the chip enters a static state. An enabled interrupt or a hardware reset can bring the chip back to its normal operating mode from idle or powerdown. See Chapter 12, “Special Operating Modes,” for details on the power-saving modes.

MCS 251 microcontrollers use an instruction set that has been expanded to include new opera- tions, addressing modes, and operands. Many instructions can operate on 8-, 16-, or 32-bit oper- ands, providing easier and more efficient programming in high-level languages such as C. Additional new features include the TRAP instruction, a new displacement addressing mode, and several conditional jump instructions. Chapter 5, “Programming,” describes the instruction set and compares it with the instruction set for MCS 51 microcontrollers.

You can configure the 8XC251Sx to run in binary mode or source mode. Either mode executes all of the MCS 51 architecture instructions and all of the MCS 251 architecture instructions. How- ever, source mode is more efficient for MCS 251 architecture instructions, and binary mode is more efficient for MCS 51 architecture instructions. In binary mode, object code for an MCS 51 microcontroller runs on the 8XC251Sx without recompiling.

If a system was originally developed using an MCS 51 microcontroller, and if the new 8XC251Sx-based system will run code written for the MCS 51 microcontroller, performance will be better with the 8XC251Sx running in binary mode. Object code written for the MCS 51 mi- crocontroller runs faster on the 8XC251Sx.

However, if most of the code is rewritten using the new instruction set, performance will be better with the 8XC251Sx running in source mode. In this case the 8XC251Sx can run significantly fast- er than the MCS 51 microcontroller. See Chapter 4, “Device Configuration,” for a discussion of binary mode and source mode.

MCS 251 microcontrollers store both code and data in a single, linear 16-Mbyte memory space. The 8XC251Sx can address up to 256 Kbytes of external memory. The special function registers (SFRs) and the register file have separate address spaces. See Chapter 3, “Address Spaces,” for a description.

2.2MCS 251 MICROCONTROLLER CORE

The MCS 251 microcontroller core contains the CPU, the clock and reset unit, the interrupt han- dler, the bus interface, and the peripheral interface. The CPU contains the instruction sequencer, ALU, register file, and data memory interface.

2-4

Page 35 Page 37
Page 36
Image 36
Intel 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB, Embedded Microcontroller manual MCS 251 Microcontroller Core
Page 35 Page 37

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.