4.8
Summary
In this chapter we have covered FPGA programming technologies including antifuse, SRAM, and EPROM technologies; the programming technology is linked to all the other aspects of a programmable ASIC. Table
4.7
summarizes the programming technologies and the fabrication processes used by programmable ASIC vendors.
|
TABLE 4.7
Programmable ASIC technologies.
|
|
|
Actel
|
Xilinx LCA
|
Altera EPLD
|
Xilinx EPLD
|
|
Programming
technology
|
Poly–diffusion
antifuse, PLICE
|
Erasable SRAM
ISP
|
UV-erasable EPROM (MAX 5k)
EEPROM (MAX 7/9k)
|
UV-erasable EPROM
|
|
Size of
programming
element
|
Small but requires contacts to metal
|
Two inverters plus pass and switch devices. Largest.
|
One
n
-
channel EPROM device.
Medium.
|
One
n
-
channel EPROM device.
Medium.
|
|
Process
|
Special: CMOS plus three extra masks.
|
Standard CMOS
|
Standard EPROM and EEPROM
|
Standard EPROM
|
|
Programming method
|
Special hardware
|
PC card, PROM, or serial port
|
ISP (MAX 9k) or EPROM programmer
|
EPROM programmer
|
|
|
|
|
|
|
|
|
QuickLogic
|
Crosspoint
|
Atmel
|
Altera FLEX
|
|
Programming
technology
|
Metal–metal antifuse, ViaLink
|
Metal–polysilicon antifuse
|
Erasable SRAM.
ISP.
|
Erasable SRAM.
ISP.
|
|
Size of
programming
element
|
Smallest
|
Small
|
Two inverters plus pass and switch devices. Largest.
|
Two inverters plus pass and switch devices. Largest.
|
|
Process
|
Special, CMOS plus ViaLink
|
Special, CMOS plus antifuse
|
Standard CMOS
|
Standard CMOS
|
|
Programming method
|
Special hardware
|
Special hardware
|
PC card, PROM, or serial port
|
PC card, PROM, or serial port
|
All FPGAs have the following key elements:
-
The programming technology
-
The basic logic cells
-
The I/O logic cells
-
Programmable interconnect
-
Software to design and program the FPGA
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