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EPM1270GF100A 数据表(PDF) 17 Page - Altera Corporation |
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EPM1270GF100A 数据表(HTML) 17 Page - Altera Corporation |
17 / 86 page Chapter 2: MAX II Architecture 2–9 Logic Elements © October 2008 Altera Corporation MAX II Device Handbook Normal Mode The normal mode is suitable for general logic applications and combinational functions. In normal mode, four data inputs from the LAB local interconnect are inputs to a four-input LUT (see Figure 2–7). The Quartus II Compiler automatically selects the carry-in or the data3 signal as one of the inputs to the LUT. Each LE can use LUT chain connections to drive its combinational output directly to the next LE in the LAB. Asynchronous load data for the register comes from the data3 input of the LE. LEs in normal mode support packed registers. Dynamic Arithmetic Mode The dynamic arithmetic mode is ideal for implementing adders, counters, accumulators, wide parity functions, and comparators. An LE in dynamic arithmetic mode uses four 2-input LUTs configurable as a dynamic adder/subtractor. The first two 2-input LUTs compute two summations based on a possible carry-in of 1 or 0; the other two LUTs generate carry outputs for the two chains of the carry-select circuitry. As shown in Figure 2–8, the LAB carry-in signal selects either the carry-in0 or carry-in1 chain. The selected chain’s logic level in turn determines which parallel sum is generated as a combinational or registered output. For example, when implementing an adder, the sum output is the selection of two possible calculated sums: data1 + data2 + carry in0 or data1 + data2 + carry-in1 Figure 2–7. LE in Normal Mode Note to Figure 2–7: (1) This signal is only allowed in normal mode if the LE is at the end of an adder/subtractor chain. data1 4-Input LUT data2 data3 cin (from cout of previous LE) data4 addnsub (LAB Wide) clock (LAB Wide) ena (LAB Wide) aclr (LAB Wide) aload (LAB Wide) ALD/PRE CLRN D Q ENA ADATA sclear (LAB Wide) sload (LAB Wide) Register chain connection LUT chain connection Register chain output Row, column, and DirectLink routing Row, column, and DirectLink routing Local routing Register Feedback (1) |
类似零件编号 - EPM1270GF100A |
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类似说明 - EPM1270GF100A |
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