文档介绍：FPGA Introduction
Presented by:
Eng. Ahmed Mohsen
August 2003
Programmable devices
! PROM
" Mask Programmable (programmed only by the
manufacturer)
" Field Programmable (programmed by the end-user)
! EPROM, EEPROM
! Programmable Logic Devices (PLD)
" Array of AND gates connected to array of OR gates
! PAL :programmable AND-plane followed by a fixed OR-plane
! PLA :both AND and OR planes are programmable
! Mask Programmable Gate Array (MPGA)
! Field Programmable Gate Arrays (FPGA)
Programmable Logic Devices
(PLD)
Inputs (logic variables)
Used mainly to
implement
combinatorial logic
functions:
“Sum of products”
F=AB+CD’ etc.
Outputs (logic functions)
Field Programmable Gate Arrays.
(FPGA)
It is a two-dimensional array of logic blocks and flip-
flops with a means for the user to configure:
1. the interconnection between the logic blocks.
2. the function of each block.
Simplified version of FPGA internal architecture:
FPGA Advantages
! FPGAs were introduced as an alternative to custom
ICs for implementing glue logic due to:
" improved density relative to discrete SSI/ponents
(within around 10x of custom ICs)
" with the aid puter aided design (CAD) tools circuits
could be implemented in a short amount of time (no physical
layout process, no mask making, no IC manufacturing)
! Lower cost of development, sometimes called non-recurring
engineering (NRE)
! Shortens time-to-market TTM
! the density (gates/area) of FPGAs continued to grow through where
now major data processing functions can be implemented on a single
FPGA.
Comparison with ASIC and µP
! FPGAs continue pete with custom ICs for special
processing functions (and glue logic) but now pete
with microprocessors in dedicated and embedded applications.
" Performance advantage over microprocessors because circuits can be
customized for the task at hand. Microprocessors must provide special
functions in software (many