参数资料
型号: EP20K600EFC1020-1ES
英文描述: FPGA
中文描述: FPGA的
文件页数: 23/114页
文件大小: 1623K
代理商: EP20K600EFC1020-1ES
16
Altera Corporation
APEX 20K Programmable Logic Device Family Data Sheet
Cascade Chain
With the cascade chain, the APEX 20K architecture can implement
functions with a very wide fan-in. Adjacent LUTs can compute portions
of a function in parallel; the cascade chain serially connects the
intermediate values. The cascade chain can use a logical AND or logical OR
(via De Morgan’s inversion) to connect the outputs of adjacent LEs. Each
additional LE provides four more inputs to the effective width of a
function, with a short cascade delay. Cascade chain logic can be created
automatically by the Quartus II software Compiler during design
processing, or manually by the designer during design entry.
Cascade chains longer than ten LEs are implemented automatically by
linking LABs together. For enhanced fitting, a long cascade chain skips
alternate LABs in a MegaLAB structure. A cascade chain longer than one
LAB skips either from an even-numbered LAB to the next even-numbered
LAB, or from an odd-numbered LAB to the next odd-numbered LAB. For
example, the last LE of the first LAB in the upper-left MegaLAB structure
carries to the first LE of the third LAB in the MegaLAB structure. Figure 7
shows how the cascade function can connect adjacent LEs to form
functions with a wide fan-in.
Figure 7. APEX 20K Cascade Chain
LE1
LUT
LE2
LUT
d[3..0]
d[7..4]
d[(4
n – 1)..(4n – 4)]
d[3..0]
d[7..4]
LE
n
LE1
LE2
LE
n
LUT
AND Cascade Chain
OR Cascade Chain
d[(4
n – 1)..(4n – 4)]
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EP20K600EFC1020-1X FPGA
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相关代理商/技术参数
参数描述
EP20K600EFC1020-1X 制造商:未知厂家 制造商全称:未知厂家 功能描述:FPGA
EP20K600EFC1020-2 制造商:未知厂家 制造商全称:未知厂家 功能描述:FPGA
EP20K600EFC1020-2ES 制造商:未知厂家 制造商全称:未知厂家 功能描述:FPGA
EP20K600EFC1020-2X 制造商:未知厂家 制造商全称:未知厂家 功能描述:FPGA
EP20K600EFC1020-3 制造商:未知厂家 制造商全称:未知厂家 功能描述:FPGA