功率消耗InputandOutputLogicLevels输入输出逻辑位准.PPT

* Program for 2-input OR gate -- Program for 2-input OR gate entity OR_1 is port (A,B: in bit; X: out bit); end entity OR_1 architecture ORfunction of OR_1 is Begin X = A or B; end architecture ORfunction; * Programming VHDL 註解符號是- - 資料流描述法(Data flow descriptions) X = A 資料從輸入流到輸出的過程。 行為描述法(Behavioral description 被使用在邏輯功能太複雜的情況 它根據特定時間下的函數與輸入狀態來描述邏輯的操作 X =‘1’ when (A=‘0’) else ‘0’ * 邏輯運算子 運算子 說明 and 只有在所有輸入信號為1時，才回傳0 or 當任何輸入信號為1時，就回傳1 not 如果輸入信號為0，則回傳1；如果輸入為1，則回傳0 nand 當任何輸入信號為0時，就回傳1 nor 當所有輸入信號為0時，則回傳1 xor 當只有一個輸入信號為1時，回傳1 xnor 當兩個輸入信號同時為1或0時，回傳1 * Program for 3-input AND gate -- program for 3-input AND gate entity AND_gate is port (A, B, C,: in bit; X: out bit); end entity AND_gate; architecture ANDfunction of AND_gate is Begin X = A and B and C; end architecture ANDfunction * Figure 3--72 Thomas L. FloydDigital Fundamentals, 8e Copyright ?2003 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458All rights reserved. 本章摘要 * Figure 3--87 Thomas L. FloydDigital Fundamentals, 8e Copyright ?2003 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458All rights reserved. 習題 3-25 請根據圖3-87的示波器顯示波形，判斷 tPLH與tPHL的值。兩個通道上的刻度單位均為V /div sec /div。 * Figure 3--97 Thomas L. FloydDigital Fundamentals, 8e Copyright ?2003 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458All rights reserved. 兩個輸入端都輸入1, 輸出端才輸出1. 習題 3-49 請設計一組能適用於圖3-97中米黃色方塊的電路，這個電路使汽車在啟動開關關閉後，於車大燈開關仍然開啟的條件下，會持續電亮15秒後才自動熄滅。假設使車大燈熄滅所需的信號是LOW狀態。 點火開關 車大燈開關 * End of Chapter 3 * * 效能特性與參數 輸入輸出邏輯準位 * SPP = tpPD 例題 3-22 某個邏輯閘 tp=5ns, ICCH=1ma, 且ICCL=2.5ma, VCC=5V, 求其SPP值 PD=VCC[(ICCH+ICCL)/2]=5[(1ma+2.5ma)/2]=8.75mw SPP=tpPD=(5ns)(8,75mw)=43.75pJ 效能特性與參數 速度功率乘積 速度功率乘積(SPP)是評量邏輯電路效能另一項參數, 越小越好 * Figure 3--53 The LS TTL NAND gate output fans out to a maximum of 20 LS TTL gate inputs. Thomas L. FloydDigital Fundamentals, 8e Copyright ?2003 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458All rights reserved. Fanout扇出能力