Platform for embedded control -

Platform for embedded control

STMicroelectronics' FIVE embedded controller platform, integratesthe benefits of microcontrollers, together with a dedicatedarchitecture, the 'Decision Processor', optimised for high-levelalgorithms and a visual programming approach.

The family of Intelligent Controller Units (ICU) based on FIVEplatform unite two key concepts: a hardware architecture thatcombines a powerful microcontroller with a patented DecisionProcessor that accelerates the sophisticated algorithms that arebeing increasingly needed in embedded applications, and advancedvisual programming tools that minimize product development time andallow product proliferation and evolution to be accomplished quicklyand robustly.

Each ICU device contains a high performance 8-bit registerfile-based CPU, analog and digital peripherals, non-volatile memory(EPROM, EEPROM or Flash) and the Decision Processor.

The ST408 devices offer 55 instructions, including hardwaremultiply and divide, and deliver 2MIPS performance, while the ST508range features an enhanced instruction set (105 instructions), 4MIPSperformance and on-chip memories up to 32Kbytes of Flash orEPROM/OTP, 512bytes of RAM and 4Kbytes of data EEPROM.

Also within the 508 family, a range of devices will be availablefor 2V supply systems, making this family suitable forbattery-powered devices, such as remote controls, mobile computingand PDAs.

The integrated Decision Processor provides hardware accelerationof decision-making algorithms, based on 'IF…THEN' rules andworks in tandem with the controller. In this way, designers can takeadvantage of the efficiency supported by the 'intelligent algorithms'methodology while retaining full control over critical issues such ascode density and real-time performance.

FIVE ICU register file architecture results in shortercomputational times compared to traditional accumulator-basedarchitectures, while the hardware multiplication and divisionoperations allow complex calculations to be performed at speed withoptimized code size.

Both the FIVE408 and FIVE508 families include analog/digitalperipheral options that includes A/D converters (8 and 10-bitresolution), watchdog, power-on and brown-out detectors for powermanagement, serial communications interfaces (SCI, SPI, I2C) and upto three 8- or 16-bit timers with 16-bit prescaler, that can besynchronized to drive AC three phase motors and that also provide PWMmodulation.

Also included is an 8-bit triac driver to directly drive powerdevices in all key working modes:

  • Burst (thermal and lighting applications),
  • Phase Angle Partialization (universal,
  • AC monophase motor and inductive load control), and PWMmodulation.

All FIVE 408 and FIVE 508 devices incorporate power saving andmemory readout protection mechanisms.

In addition, the on-board Flash memory available in the ST508devices allows both in situ programming (ISP), where the ICU's memorycan be programmed after the chip has been mounted on the finalapplication board, and in application programming (IAP), which allowsthe program or data code to be modified while the application isrunning. This is particularly useful in applications where thecontrol system must be able to adapt to parameters drifts or to usercharacteristics e.g. consumption habits or voice recognitionapplications.

Complementing the optimized hardware line-up, the Visual FIVE IDEdevelopment tool provides a powerful visual/graphical approach thatallows high-level programming and upward compatibility among FIVEfamilies.

Software development time is reduced because no expertise in C orassembler is required. Pin and peripheral configuration can be fullydescribed graphically so that the software is developed as a flowchart of graphical blocks. This allows the designer to focus on theapplication and facilitates fast tuning of projects.

The integrated environment includes a debugger and a programmer,enabling the downloading of the project into FIVE memory by simplyconnecting the programming board to the PC parallel port. To ensuremaximum flexibility in programming options, the FIVE software toolsuite supports both C or assembler code insertion within the VisualFIVE environment and stand-alone C compiler and assembler.

“Our aim in developing the FIVE platform was to abolish thetraditional division between cost-efficiency and flexibility,” saidAntonino Milazzotto, business unit director. “The completeintegration of hardware and software in the FIVE products, coupledwith the very wide product range and aggressive roadmap, allowsdesigners to optimize their binary code without sacrificing eitherthe time-to-market benefits of high level language programming ortheir flexibility in responding to market changes.”

There will be 57 devices available in the FIVE 408 OTP family withanother 190 devices available in the FIVE 508 Flash/EPROM familyduring this year. The FIVE 532 is a 32bit ICU that is supported bythe VisualFIVE graphical development tool.

Hardware, software and applicationsupport

The Visual FIVE software development tool provides a way toprogram ST FIVE ICUs, in a Windows environment. The visual andgraphical approach reduces assembler code writing and enablesdesigners to focus on control and system problems.

The whole project is developed as a flow chart of various blocksfor peripherals start/stop, subroutines, Decision Processoralgorithms, C and assembler parts.

The debugger allows full chip emulation, including peripherals andinterrupts and provides a graphical plot window. The programmerdownloads the project code through the programming board into ST FIVEmemory, both for OTP and erasable versions.

The FSASM assembler editor is included in Visual FIVE installationto allow project development or re-editing in assembler.

A stand alone C compiler from Raisonance is for use with the FIVE508 ICUs family .

An adaptive fuzzy modeller software tool supports design of fuzzymodels and algorithms. A neuro-fuzzy architecture enables generationof the fuzzy rules. If a set of input/output measures of the systemto be modelled is available, AFM provides the fuzzy parametersautomatically (shape and position of antecedents membership functionsand consequents values) and builds an optimized number of rules foryour system. The AFM fuzzy project can be exported to VisualFIVE,MATLAB and C code.

A number of board kits or demonstrators are available for a rangeof motor control applications. The board kits PCB (gerber and pdffiles) can be downloaded free.

Downloads are also available with examples of how to use the 408,these include programming the A/D converters and timers as wellarithemetic examples, creating a sound, managing an encoder for speedcontrol and phase angle partialization.

Published in Embedded Systems (Europe) June 2002

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