Configuration Array On-chip | Intel 8XC251SP, 8XC251SA, 8XC251SQ

8XC251SA, SB, SP, SQ USER’S MANUAL

For ROM/OTPROM/EPROM devices, user configuration bytes UCONFIG0 and UCONFIG1 can be programmed at the factory or on-site using the procedures provided in Chapter 14, “Pro- gramming and Verifying Nonvolatile Memory.” For devices without ROM/OTPROM/ EPROM, the designer should store configuration information in an eight-byte configuration array located at the highest addresses implemented in external code memory. See Table 4-1 and Figure 4-2.

Bit definitions of UCONFIG0 and UCONFIG1 are provided in Figures 4-3 and 4-4. The upper 6 bytes of the configuration array are reserved for future use. When EA# = 1, the 8XC251Sx obtains configuration information at reset from on-chip non-volatile memory at addresses FF:FFF8H and FF:FFF9H. When EA# = 0, the microcontroller obtains configuration information at reset from the external memory system using internal addresses FF:FFF8H and FF:FFF9H.

CAUTION

The eight highest addresses in the memory address space (FF:FFF8H– FF:FFFFH) are reserved for the configuration array. Do not read or write these locations. These addresses are also used to access the configuration array in external memory, so the same restrictions apply to the eight highest addresses implemented in external memory. Instructions that might inadvertently cause these addresses to be accessed due to call returns or prefetches should not be located at addresses immediately below the configuration array. Use an EJMP instruction, five or more addresses below the configuration array, to continue execution in other areas of memory.

83C251SA, SP		83C251SB, SQ
87C251SA, SP		87C251SB, SQ


FF:		FF:
8 Kbytes		16 Kbytes

For EA# = 1, the 8XC251Sx obtains configuration information from on-chip nonvolatile memory at addresses FF:FFF8H and FF:FFF9H.

FF:FFFFH

FF:FFFEH

FF:FFFDH

Reserved

FF:FFFCH

FF:FFFBH

FF:FFFAH

FF:FFF9H UCONFIG1

FF:FFF8H UCONFIG0

Detail. On-chip configuration array.

A4237-01

Figure 4-1. Configuration Array (On-chip)

4-2

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.

Intel 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB, Embedded Microcontroller Configuration Array On-chip

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

8XC251SA, SB, SP, SQ USER’S MANUAL

Figure 4-1. Configuration Array (On-chip)

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