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MCS®251 Microcontroller
8xC251TA/TB/TP/TQ and 8xC251SA/SB/SP/SQ
Microcontroller Product Brief

* Product Highlights
* Product Overview
* 8xC251SA/SB/SP/SQ
* 8xC251TA/TB/TP/TQ (New Products)
* Applications Information
* Development Tools and Programming Tools
* Project Builder 251 Evaluation Kits
* Features and Benefits
* Product Options
* ApBUILDER Interactive Applications Programming Software

Product Highlights
* Binary-code compatible with MCS® 51 microcontrollers
* Pin compatible with 44-lead PLCC and 40-lead PDIP
* MCS® 51 microcontroller sockets
* Register-based MCS® 251 microcontroller architecture
* 40-byte register file
* Registers accessible as bytes, words, and double words
* Enriched MCS® 51 microcontroller instruction set
* 16-bit and 32-bit arithmetic and logic instructions
* Compare and conditional jump instructions
* Expanded set of move instructions
* Linear addressing
* 256-Kbyte expanded external code/data memory space
* 16 Kbytes (SB/SQ), 8 Kbytes (SA/SP), or without ROM/OTPROM/EPROM
* ROM options:
* 16 Kbytes (TB/TQ), 8 Kbytes (TA/TP), or without ROM
* 16-bit internal code fetch
* 64-Kbyte extended stack space
* On-chip data RAM options:
* 1 Kbyte (SA/SB/TA/TB) or 512 bytes (SP/SQ/TP/TQ)
* 8-bit, 2-clock external code fetch in page mode
* Pipelined instruction execution unit
* Minimum 2-clocks instruction execution time
* User-selectable configurations:
* External wait states (0-3 wait states)
* Address range and memory mapping
* Page mode
* 32 Programmable I/O lines
* Seven maskable interrupt sources with four programmable priority levels
* Three flexible 16-bit timer/counters
* Hardware watchdog timer
* Programmable counter array
* High-speed output
* Compare/capture operation
* Pulse width modulator
* Watchdog timer
* Programmable serial I/O port
* Framing error detection
* Automatic address recognition
* 2nd programmable serial I/O port (UART) capability for TA/TB/TP/TQ
* High-performance CHMOS technology
* Static standby to 16 MHz operation for SA/SB/SP/SQ
* Static standby to 24 MHz operation for TA/TB/TP/TQ
* Complete system development support
* Compatible with existing tool
* New MCS® 251 microcontroller tools available:
* Compiler, assembler, debugger, ICE
* Package options (PDIP and PLCC)
Product Overview
The Intel 8xC251TA/TB/TP/TQ and 8xC251SA/SB/SP/SQ are based on the new high performance MCS® 251 microcontroller architecture. Being members of the MCS 251 microcontroller family, the 8xC251TA/TB/TP/TQ and 8xC251SA/SB/SP/SQ have the same advanced register based CPU architecture and a pipelined instruction execution unit. They use the powerful MCS 251 microcontroller instruction set, with many enhanced 8, 16 and 32-bit instructions available. The new microcontrollers are also specially designed to execute C code efficiently. Most importantly, the 8xC251TA/TB/TP/TQ and 8xC251SA/SB/SP/SQ are binary code and pin compatible with existing MCS 51 microcontrollers. They provide an easy performance upgrade path for all existing MCS 51 microcontroller applications.

The 8xC251SA/SB/SP/SQ features a rich combination of integrated peripherals that make it an even more powerful microcontroller. The Programmable Counter Array (PCA) provides the flexibility for applications that require real time compare/capture, high speed I/O and pulse width modulation capabilities. Also included is an enhanced serial port for multi-processor communications, a hardware watch dog timer, a program lock scheme for on-chip program memory and two power saving modes: idle mode and power down mode.

The 8xC251SA/SB/SP/SQ has 1 Kbyte or 512 bytes on-chip data RAM and is available with 16 Kbytes or 8 Kbytes of on-chip OTPROM/EPROM (87C251SA/SB/SP/SQ), or ROM (83C251SA/SB/SP/SQ), or ROMless (80C251SB/SQ) options. The 8xC251SA/SB/SP/SQ operates from static standby to 16 MHz clock frequency and is available in 44-pin PLCC and 40-pin package options.

8xC251TA/TB/TP/TQ (New Products)
The 8xC251TA/TB/TP/TQ is based on the MCS® 251 microcontroller architecture and has ALL of the 8xC251SA/SB/SP/SQ peripheral features plus a 2nd programmable serial I/O port (UART). In addition, the 8xC251TA/TB/TP/TQ microcontroller can perform up to 24 MHz frequency and maintains pin and code compatibility with MCS 51/151/251 microcontrollers. Similar with the 8XC251SA/SB/SP/SQ, the 8xC251TA/TB/TP/TQ has 512 bytes or 1 Kbyte of on-chip data RAM options, 8 Kbytes and 16 Kbytes of on-chip ROM or ROMless options, and is available in 44LD PLCC and 40LD PDIP package options.

Applications Information
The 8xC251TA/TB/TP/TQ and 8xC251SA/SB/SP/SQ microcontrollers are an ideal performance upgrade path for all existing MCS 51 microcontroller applications. The high performance architecture and the advanced features available in the 8xC251TA/TB/TP/TQ and 8xC251SA/SB/SP/SQ also make them ideally suited for applications requiring complex data manipulation functions and real time control capability such as printers, copiers, scanners, CD-ROM drives, tape drives, POS terminals, modems, digital phones, cellular/wireless handsets and linecards.

Development Tools and Programming Tools
Intel offers design engineers a variety of hardware and software development tools from some of the industry's leading tools suppliers. High performance, Windows* based software, full featured, real-time emulators along with flexible, fully integrated device programming support is available from many of the familiar suppliers currently supporting the MCS 51 microcontroller architecture. ApBUILDER, Intel's interactive programming software, has been upgraded to include the MCS 251 microcontroller architecture. ApBUILDER speeds up the learning curve and reduces total design time making the migration to the MCS 251 architecture easy. The Project Builder 251 Evaluation Kit brings all the hardware and software needed to begin the project together, in a low cost turnkey kit.

High performance Windows based development tools are also available from BSO/Tasking, Franklin/Keil and Production Languages Corporation (PLC). These high quality tools include ANSI C Compilers, Macro Assemblers, Source Level Debuggers, Object Librarians, Linker/Locators and Instruction Simulators. Full-featured, real-time emulators featuring DOS* or Windows based user interface and a variety of host hardware interfaces are offered by Metalink Corporation and Nohau Corporation. Flexible, fully integrated device programming support for advanced designs is available from BP Microsystems, Data I/O, Needham, SMS Mikrocomputer-Systeme GmbH, and System General Corporation.

Project Builder 251 Evaluation Kits
Project Builder 251 low cost kits give design engineers all the hardware and software tools to fully evaluate the Intel microcontroller features and performance. These turnkey kits save you design time and reduce your learning curve by providing tools for every stage of the project design cycle.

The Target Board offers maximum design flexibility to operate as a code development platform as well as a stand alone system to use in your prototype. It was even designed to use Intel's new Boot Block FLASH memory for operation in the stand alone mode.

The Project Builder Kits include a complete Integrated Development Environment commanding a powerful line of systems tools, an environment that includes Project Maintenance and graphical Program Analysis. The kit also includes ApBuilder and the Hypertext 251 User's Manual.

When you are ready to design your hardware, the kit includes interactive hardware timing models of the Intel Microcontrollers. It's like having a Data Sheet which allows you to perform "what if" timing analysis! Additionally, the kit includes schematic files and libraries of several Intel 51 and 251 boards with a CAD viewer. Start your design with a working schematic to build on! With Project Builder, you'll be Working Smarter... NOT Harder!

Features and Benefits
Features Benefits
MCS® 251 microcontroller architecture core High performance
  • Up to 5 times performance increase using existing 51 code
  • Up to 15 times performance increase using new 251 instructions
    Reduced power consumption and RFI
    Increased efficiency and support for C language programming
  • Binary code and pin compatible with MCS® 51 microcontroller Easy performance upgrade for all MCS® 51 microcontroller applications.
    Software investment protected
    Minimal development cost and effort required
    Quick time to market and quick time to money
    256 Kbytes external memory space Increased capability and flexibility to handle large software requirements
    512 bytes or 1 Kbyte on-chip data RAM Increased internal memory capacity for data manipulation and C language support
    8 Kbytes or 16 Kbytes on-chip OTP, ROM or ROMless versions supported Flexibility in using different memory options in development and production
    Programmable Counter Array (PCA) supports
  • Real-time capture and compare
  • High speed output
  • PWM
  • Flexibility and performance enhancement in real-time control applications such as:
  • Measurement of duty cycle, phase difference and frequency
  • Real-time interrupt generation and output toggling
  • Adjustable duty cycle generation
  • Hardware watch dog timer Increased system reliability
    Page mode configuration Increases the performance for external instruction fetch by 2X
    0 - 3 wait states configuration for external memory access Flexibility in external memory and peripheral interface.
    Allows the use of either fast or slow memory.
    Support seven interrupt sources, each with four interrupt priority levels Increased flexibility for event control applications

    Product Options
    Package Prefix Rom Version EPROM / OTPROM Version ROMLESS Version ROM / EPROM Bytes RAM Bytes
    N, P 83C251SA 87C251SA 80C251SB 8K 1K
    N, P 83C251SB 87C251SB 80C251SB 16K 1K
    N, P 83C251SP 87C251SP 80C251SQ 8K 512
    N, P 83C251SQ 87C251SQ 80C251SQ 16K 512
    N, P 83C251TA N/A 80C251TB 8K 1K
    N, P 83C251TB N/A 80C251TB 16K 1K
    N, P 83C251TP N/A 80C251TQ 8K 512
    N, P 83C251TQ N/A 80C251TQ 16K 512

    ApBUILDER Interactive Applications Programming Software
    ApBUILDER is a powerful tool which generates source code for programming Intel's Embedded Processors with a click of a mouse! This powerful design tool speeds up the learning curve and reduces the total design time for the embedded control application programmer. Each screen of ApBUILDER is context sensitive and linked to Intel's hypertext device user's manuals.

    Just use your mouse to touch a bit, flag, register or instruction then hit the "Manual" button and the built-in hypertext link will take you right to the paragraph in the device user's manual. With Intel's hypertext manuals and data sheets its easy to make copies or share them over a network too.

    To obtain ApBUILDER and the Hypertext User's Manuals FREE, just download them from the Intel home page on the World Wide Web:

    WWW: www.intel.com
    or ftp: ftp.intel.com
    Select "Embedded Design Products" on the Intel home page.

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