13 - 22-Sep-103:27 PMJ-K FF, Counters1University of...

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Unformatted text preview: 22-Sep-103:27 PMJ-K FF, Counters1University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoEEL 3701EEL 3701Menu Clocks and Master-Slave Flip-Flops J-K and other Flip-Flops Truth table & excitation table Adders (see [Lam: pg 130]) CountersLook into my ...1University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoEEL 3701EEL 3701Master-Slave Flip-Floptc= time when signals changeMaster-Slave Latch/Flip-FlopALUetc.tw= digital systems do their work here, others finish their work in this phaseM t di it ltt th i it t bt bll i thCLKtctwSRQQECLK2University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoMost digital systems expect their inputs to be stable very early in the tcphase of the clock. As drawn, it is possible for S and/or R to change while CLK = 1 (during tc).Q (active-high and -low) may change during time tceven though other hardware expect them to be stable!!22-Sep-103:27 PMJ-K FF, Counters2University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoEEL 3701EEL 3701Master-Slave Flip-FlopQ: How do we solve this problem?A:Use 2 latchs, one master, one slave. Signals do not change d i(Thi idi itll tith 3rdtididduring tc. (This is a digital-only solution; the 3rdoption discussed earlier.)Q: Why?A:Now {Q(H), Q(L)} will not change until tw. Hence, inputs to other systems are stable during tc.MasterSlaveMaster-Slave S-R Flip-Flop3University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoSRQQESRQQECLKtctwCLKtctwEEL 3701EEL 3701Master-Slave JK FFGated S-R LatchQ(L)S(H)E(H)Pre-SetSQQ(H)Pre-ClearR(H)RQEMaster-Slave J-K FF(Falling Edge Clock)RQRQMasterSlaveQQSSKJJ-K FF withfallingedge-clockJQS4University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoLogicWorks> With master-slave FFs we have a completely digitalsolution to the stable input problem. No oscillation occurs!!!!JK_from_M-S_SR*.cctRQERQEKQR22-Sep-103:27 PMJ-K FF, Counters3University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoEEL 3701EEL 3701Flip-FlopsMaster-Slave J-K FF(Rising Edge Clock)J-K FF with risingedge-clockSla eJ-K FF withfallingedge-clockJKQQKQEKQEMasterSlaveQQJJT-FF using JKD-FF using JKD-FF using SRSRJKQQSR5University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoTJKQQDJKQQDSRQQHow about constructing a JK with a D?Hint: D = J /Q + /K QSRSRSREEL 3701EEL 3701D-FF using Two MUXs Designed by Alex Kagioglu, a UF EEL 4712 student, 20081SelY2-input MUX1SelY2-input MUXQ(H)D(H)CLKCLK6University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoSeld-ff_mux.bdfd-ff_mux.vwfmux2to1.vwf22-Sep-103:27 PMJ-K FF, Counters4University of Florida, EEL 3701 File 13 Drs. Schwartz & ArroyoEEL 3701EEL 3701J-K Flip-FlopNext State Truth Q Q+JK111Excitation Table for J-K FFJK Q Q+11111Table for J-K FFJKQ+FunctionQHold1ReseAbbreviated Next State Truth Table for J-K FF1111111111111Abbreviated Excitation 7University of Florida, EEL 3701 File 13 Drs. Schwartz & Arroyo Drs....
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13 - 22-Sep-103:27 PMJ-K FF, Counters1University of...

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