Product category:
Microprocessors, Microcontrollers and DSPs
News Release from: Fujitsu Microelectronics Europe | Subject: MB90F897
Edited by the Electronicstalk Editorial
Team on 24 February 2004
Dual-operation Flash adds to MCU
flexibilty
The MB90F897 is the latest addition to Fujitsu's portfolio of microcontrollers with Controller Area Network (CAN) interfaces.
The MB90F897 is the latest addition to Fujitsu's portfolio of microcontrollers with Controller Area Network (CAN) interfaces This latest product has been designed for automotive body control and comfort applications
This article was originally published on Electronicstalk on 16 Feb 2001 at 8.00am (UK)
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Housed in a 48-pin QFP package of a mere 7mm square, this small footprint incorporates the 16LX CPU core and peripherals such as timers, four PWM channels, two UARTs, an A/D convertor as well as 64Kbyte of Flash memory and 2Kbyte RAM.
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In addition to TTL and CMOS levels, "automotive levels" can be selected with VIL set at half Vcc.
This is a critical feature as ground levels in vehicles often show offsets of several volts.
The MB90F897 can be specified for 125C operation and is pin compatible with the MB90385 and MB90455 series.
The company now offers more 50 different 16LX CAN products.
Fujitsu is actively growing its core competence in embedded Flash technology since the introduction of the first 16bit microcontroller with single voltage Flash technology and 10K write-erase cycles in 1997.
Recent specifications for 100,000 write/erase cycles or high temperature specifications underline that the process technology has achieved a high level of stability.
The new dual-operation Flash technology inherits these feature and expands the functionality: It allows fast EEPROM emulation and reliable self-programming because the 64Kbyte Flash macro is divided into two banks.
In each Flash memory bank write, read and erase operation can be performed separately.
The smaller bank consists of four sectors of 4Kbyte each.
Any sector can be erased individually.
Writing to Flash is possible in units of one word.
Conventional Flash memory requires the CPU to execute code from RAM while the Flash content is updated - therefore during reprogramming no read from Flash is possible.
In dual-operation, Flash program execution continues in one bank while, for instance, data are updated in the other bank.
Integrated EEPROM functionality in embedded Flash has many advantages compared with external EEPROM ICs, allowing more flexible memory management and higher read/write speeds than separate EEPROM.
Often this functionality makes external EEPROM ICs redundant - which reduces PCB and footprint complexity.
Internal memory is always the preferred choice when memory content needs to be protected from manipulation.
Writing one word into the Flash memory can be completed in just 16us, which is much faster than writing to conventional external EEPROM (which may take about 50us per word).
Many Flash microcontroller applications require a CPU-controlled software update (self-programming).
The advantage of dual operation Flash is that the CPU can always operate from one memory bank while the other bank is rewritten.
This concept makes it easy to cope with events such as interrupts or reset during reprogramming.
Interrupt vectors are normally located in the highest sector of the upper bank.
However, during programming the upper bank cannot be accessed.
Therefore, a special register is provided which switches the internal interrupt vectors to the highest sector of the lower bank, thus allowing Interrupt Services during write/erase procedures.
Detection of completion of writing/erasing can be achieved by interrupt.
This increases system performance.
The reset vector is hard-wired, pointing to 0xFFE000 to ensure correct reset procedure at any time.
To prevent accidental write or erase, a special write enable/protect register is provided.
Once a sector is write protected only a power-up or an external reset can release the protection.
Each sector can be protected individually.
For these new products a comprehensive development tool environment is available. Request a free brochure from Fujitsu Microelectronics Europe ...
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