FPGA technology in detail
FPGAs are chips, which are programmed by the customer to perform the desired functionality. The chips may be programmed either
once: Antifuse technology, e.g. devices manufactured by Quicklogic
several times: Flash based, e.g. devices manufactures by Actel
dynamically: SRAM based, e.g. devices manufactured by Actel, Altera, Atmel, Cypress, Lucent, Xilinx
Each technology has its own advantages, which shall be discussed only very briefly:
Antifuse FPGAs:
devices are configured by burning a set of fuses. Once the chip is configured, it cannot be altered any more.
bug fixes and updates possible for new PCBs, but hardly for already manufactured boards.
ASIC replacement for small volumes.
Flash FPGAs:
devices may be re-programmed several thousand times and are non-volatile, i.e. keep their configuration after power-off
with only marginal additional effort, the chips may be updated in the field expensive
re-configuration takes several seconds
SRAM FPGAs:
currently the dominating technology unlimited re-programming
additional circuitry is required to load the configuration into the FPGA after power-on
re-configuration is very fast, some devices allow even partial re-configuration during operation
allows new approaches and applications- buzzword reconfigurable computing, e.g. a circuit, that searches for a specific
DNA pattern, or a mobile phone that downloads the latest protocol update
