SR Latch (NAND version) S′R'Q 0 1 dIsallowed 0110Set 100 1 Reset Qn Qn Hold
S’R’ Latch (NAND version) S’ R’ Q Q’ 0 0 0 1 1 0 1 1 1 0 Set 0 1 Reset 1 1 Disallowed S’ R’ Qn+1 Qn+1 ’ Qn Qn ’ Hold
SR Latch (NAND version) Truth table 0011110 R’S,Oo畔 Function 0 dIsallowed 0 00 11Disallowed 0 0 100 Reset 0 Reset 1001Set Characteristic Equation 1011s 100 Hold Qntl=s+rQn 1111|Hod S+R=1
S’R’ Latch (NAND version) 0 0 0 1 1 1 0 0 1 0 1 1 1 0 0 1 0 1 1 0 0 1 0 0 0 0 1 1 1 1 1 1 R’ S’ Qn Qn+1 Function Disallowed Disallowed Reset Reset Set Set Hold Hold Truth table 00 0 01 11 10 1 R’S’ Qn 0 0 1 1 × 0 1 × Qn+1=S+R’Qn S’+R’=1 Characteristic Equation
SR latch (NOR version) R(Reset) S RIQ Q Q 010 Set state 0010 0101 0001 Reset state Q S Set) 00 Undefined (a)Logic diagram b)Function table SR: set-reset bi-stable element with two extra inputs; note the " undefined"output for s=R=1
SR latch (NOR version) -- SR: “set-reset”, bi-stable element with two extra inputs; note the “undefined” output for S=R=1
SR latch (NOR version) R S R SQQ 计1| Function Q00011110 0000H 0 010 Set 1000|R 0R Characteristic Equation 100 Disallowed 1 110Disallowed Qntl=s+rQn SR=O
0 0 0 0 1 1 0 0 1 0 1 0 1 0 0 0 0 1 1 1 0 1 0 1 0 0 1 1 1 1 1 0 R S Qn Qn+1 Function Disallowed Disallowed Reset Reset Set Set Hold Hold 00 0 01 11 10 1 R S Qn 0 1 1 0 0 1 × × Qn+1=S+R’Qn SR=0 Characteristic Equation SR latch (NOR version)
SR Latches S( Set) Q r Q R(Reset (a)Logic diagram R( Reset) r Q S(Set) (a)Logic diagram
SR Latches S R Q Q’ S R Q Q’