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5M1270ZT64A4N 参数 Datasheet PDF下载

5M1270ZT64A4N图片预览
型号: 5M1270ZT64A4N
PDF下载: 下载PDF文件 查看货源
内容描述: MAX V器件手册 [MAX V Device Handbook]
分类和应用:
文件页数/大小: 166 页 / 4016 K
品牌: ALTERA [ ALTERA CORPORATION ]
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Chapter 2: MAX V Architecture  
2–9  
Logic Elements  
improves device utilization because the device can use the register and the LUT for  
unrelated functions. Another special packing mode allows the register output to feed  
back into the LUT of the same LE so that the register is packed with its own fan-out  
LUT. This mode provides another mechanism for improved fitting. The LE can also  
drive out registered and unregistered versions of the LUT output.  
LUT Chain and Register Chain  
In addition to the three general routing outputs, the LEs within a LAB have LUT chain  
and register chain outputs. LUT chain connections allow LUTs within the same LAB  
to cascade together for wide input functions. Register chain outputs allow registers  
within the same LAB to cascade together. The register chain output allows a LAB to  
use LUTs for a single combinational function and the registers for an unrelated shift  
register implementation. These resources speed up connections between LABs while  
saving local interconnect resources. For more information about LUT chain and  
register chain connections, refer to “MultiTrack Interconnect” on page 2–14.  
addnsub Signal  
The LE’s dynamic adder/subtractor feature saves logic resources by using one set of  
LEs to implement both an adder and a subtractor. This feature is controlled by the  
LAB-wide control signal addnsub. The addnsubsignal sets the LAB to perform either  
A + B or A – B. The LUT computes addition; subtraction is computed by adding the  
two’s complement of the intended subtractor. The LAB-wide signal converts to two’s  
complement by inverting the B bits within the LAB and setting carry-in to 1, which  
adds one to the LSB. The LSB of an adder/subtractor must be placed in the first LE of  
the LAB, where the LAB-wide addnsubsignal automatically sets the carry-in to 1. The  
Quartus II Compiler automatically places and uses the adder/subtractor feature  
when using adder/subtractor parameterized functions.  
LE Operating Modes  
The MAX V LE can operate in one of the following modes:  
“Normal Mode”  
“Dynamic Arithmetic Mode”  
Each mode uses LE resources differently. In each mode, eight available inputs to the  
LE, the four data inputs from the LAB local interconnect, carry-in0 and carry-in1  
from the previous LE, the LAB carry-in from the previous carry-chain LAB, and the  
register chain connection are directed to different destinations to implement the  
desired logic function. LAB-wide signals provide clock, asynchronous clear,  
asynchronous preset/load, synchronous clear, synchronous load, and clock enable  
control for the register. These LAB-wide signals are available in all LE modes. The  
addnsubcontrol signal is allowed in arithmetic mode.  
The Quartus II software, along with parameterized functions such as the library of  
parameterized modules (LPM) functions, automatically chooses the appropriate  
mode for common functions such as counters, adders, subtractors, and arithmetic  
functions.  
December 2010 Altera Corporation  
MAX V Device Handbook  
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