ABC of electronics terms
(To find chips for distinct functions, see the functional pages.)
See local for manufacturers of fans
Frequently Asked Questions
Fastener
Facsimile. A way to send paper documents via a telephone line. A fax is a combined scanner and printer.
Field Bus
www.fieldbus.org/
File type
Finger print
NEC makes a finger print scanner called 'NEC TouchPass'. It has 60% marketshare world-wide.
See also:
See IEEE 1394.
Flash EPROM
This is a special kind of EEPROM that can be made in big sizes and is
meant to replace the old UV-EPROM unlike the normal EEPROM, that
usually has a small memory size and is meant to keep a limited
number of settings or other user data. The normal EEPROM used
to have a serial interface to save on pins, both on the EEPROM
and on the MCU and to save on PCB-connections. Flash EEPROM's
have the usual fast many*8 interface of the UV-EPROM's, so it can
be used as regular MCU or CPU memory.
For a while the manufacturers tried to introduce many*16 or
even many*32 bits EPROM*'s but that proved to be to expensive.
It's cheaper to use a couple of many*8's in parallel. And shortly
after, it proved better and cheaper to use the CPU's 32 or 16
bits bus first in 8 bits mode and copy the complete ROM into
DRAM and then run it from there.
See also EEPROM, EPROM*, PROM*, ROM.
Floppy Disk Drive
Forth is an interpreted stack based programming language, whose fans seem
mostly mesmerised by the usage of the more computer oriented postfix operator
notation (also called reversed polish notation and made famous by the HP
calculators). I bought a book about Forth once but the author started in the
introduction to explain that even the programmer himself usually couldn't
understand the source code that he had written himself the previous day.
Another problem seemed to be that the language was quite natural as long
as all cells on the stack were of the same size (so 16 bits in those days),
but as soon as you also started to use longs (of 32 bits) and floats (of
32 or 64 bits) the stack handling would soon become very tedious. At that
point I stopped reading considering that Forth was not a serious software
engineering language. Use C instead! For more advanced projects Java should
be considered (or C++ as a second choice). C is still the standard
language (on which all later serious languages like C++, Java and Javascript
are based). Languages like Forth, Lisp and Prolog are clearly of another order
and I have never seen them used for serious engineering work.
Ah, I just remembered that when the PCI bus just started and they still
wanted it to be implemented in all kinds of computers in a computer independent
way, they proposed that every card would have an on card driver written in Forth.
The host computer could either interpret this program or compile it into
native code. I very much doubt that it's still done this way, since PC-cards
on the ISA bus were also considered to have their drivers in on-board
ROM's but this proved too expensive (and inflexible as regards to driver upgrades)
so allmost all drivers came on floppy and later CD-ROM making the installment
of PC-cards or exchanging them between computers or migrating a harddisk with
filesystem from system to system the true hell that it is nowadays.
Back to Forth though:
Also see the MISC mailing list in the mailing lists section.
It's a processor architecture aimed at processing Forth efficiently.
Field Programmable Analog Array.
Enables fast design of complex analog circuits.
Motorola has left this market in 199806 according to a senior engineering
contact at Motorola who had helped develop the part. He wrote me:
'It was a great device and fun while it lasted (sigh), but alas, it is no more.'
See also CPLD and FPGA (next entry on this page) and TRAC.
Field Programmable Gate Array
This is a large chip with an array of cells, with each a couple of memory elements,
and logic. You determine how all the elements are connected. So you can program how
your hardware behaves. The configuration of these chips is often loaded at power-up
from a serial EEPROM I think.
This is a 'cheap' way to design your own chips. All the components are already on the
chip, but 'in the field' you program them to make the right connections between the
components.
Cheap is not really true for large amounts since the chip will use a lot of energy
for the components that you're not really using. These components are also expensive
because they carry a lot of unused silicon around. They may also be slow. Startup time
may be hindered by the fact that their functionality needs to be loaded from a serial ROM.
The software needed to achieve the functionality may also be expensive and getting your
personal used to the software may also take time. However once the design is ready
and tested there may be an easy path to having the design being mass produced in a real
ASIC. Xilinx became big making these things.
FPGA manufacturers:
FPGA's are so large and complex by now that you can design your own
processors in them:
See also CPLD, FPAA (previous entry) and VHDL.
Chips:
FPGA
See also:
More info
See also:
CPLD and PLD.
Digital Systems Design and Prototyping Using Field Programmable Logic
- Zoran Salcic and Asim Smailagic
- Kluwer Academic Publishers
- Norwell, MA
- tel: +1-617-871-6600
- Overview of PLD and FPGA technology, applications and design techniques.
- See EDN Europe, 19971009/pg 20
Fuzzy Logic
