FPGA basics

Aug 22, 2009 21 Replies

An FPGA is quite a different device than a microcontroller like a PIC.

An FPGA essentially contains a large number of gates, flip-flops, and other logic devices that your "program" can connect together to perform some (or several) useful logic functions.

The FPGA vendor should have development software available. I've used Altera FPGAs and CPLDs, and developed the configuration files using Altera's free software. It allows you to develop the design using schematic diagrams (you can even place TTL-equivalent parts on the schematic if you wish) or with a High Level Design Language (HDL) - I usually use a combination of schematic and AHDL (Altera's HDL). Often some parts of my projects are easier to describe in AHDL, while others are easier as schematics.

The FPGA will require one or more power supplies, a programming connector, and possibly a configuration EEPROM.

You will probably have to build some surrounding circuits to get outside world signals into the FPGA, and to get the outputs from the FPGA to the outside world.

Peter Bennett, VE7CEI peterbb4 (at) interchange.ubc.ca GPS and NMEA info: http://vancouver-webpages.com/peter Vancouver Power Squadron: http://vancouver.powersquadron.ca

Look, depending on the particular part it ranges from easier than a PIC to far worse than a multi-core CPU. It covers that whole range, and maybe more. They go from CPLDs to chips large enough to have multiple CPU cores with attendant code. Is this clear yet? If you had been reading s.e.d long enough you would have heard kvetching about elaborate power sequencing required by some large parts.

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