nonpage mode

npn transistor

OTPROM

p-channel FET

p-type material

page mode

PC

peripheral cycle

program memory

powerdown mode

PWM

real-time wait state

rel

reserved bits

response time

GLOSSARY

Conventional method for accessing external memory where code fetches require a two-state bus cycle. See also page mode.

A transistor consisting of one part p-type material and two parts n-type material.

One-time-programmable read-only memory, a version of EPROM.

Afield-effect transistor with a p-type conducting path.

Semiconductor material with introduced impurities (doping) causing it to have an excess of positively charged carriers.

Method for reducing the time for external code fetches where subsequent code fetches to the same 256-byte “page” of memory require only a one-state bus cycle.

Program counter.

The cycle at which the 8XC251SA, SB, SP, SQ peripherals operate. This is equal to six state times.

A part of memory where instructions can be stored for fetching and execution.

The power conservation mode that freezes both the core clocks and the peripheral clocks.

Pulse-width modulated (outputs).

A wait state whose delay time can be adjusted dynamically by the programmer by means of registers.

Asigned (two's complement) 8-bit, relative destination address. The destination is -128 to +127 bytes relative to the first byte of the next instruction.

Register bits that are not used in this device but may be used in future implementations. Avoid any software dependence on these bits. In the 8XC251SB, the value read from a reserved bit is indeterminate; do not write a “1” to a reserved bit.

The amount of time between the interrupt request and the resulting break in the current instruction stream.

Glossary-5

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Intel 8XC251SB, 8XC251SA, 8XC251SP, 8XC251SQ, Embedded Microcontroller manual Otprom
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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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