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5.10 MULTIPLE OUTPUT FUNCTIONS WITH DON'T CARES 223

H , and their canonical SOP/EXSOP transformations now become

F = m(3, 5, 6, 8, 9, 12, 15) = (3, 5, 6, 8, 9, 12, 15)

and (5.54)
H = m(l, 2, 4, 7, 10, 11, 12, 13) = m(l, 2, 4, 7, 10, 11, 12, 13).

Here, for function F, the don't cares are choosen to be 0] = 0 4 = 0 n = 0 and 0 5 = 1.
For function H the don't cares are assigned the values 0 5 = 0 6 = 0 8 = 0 15 = 0 and
02 = 0i i = 1 . The don't-care values are chosen in agreement with STEP (6) of the heuristics
for CRMT minimization given previously. Thus, the CD columns and the AB rows have
simple subfunctions of the type X and X © Y to improve chances for an optimum result.
Function F in Eqs. (5.53) is now recast as the contracted CRMT form

F CD = (CDfo) © (CZ>/0 © (CA/2) © (CD/ 3)
= (CD) A 0 (CD)(A © 5) © (CD)AB © (CD)(A © fl)
(5.55)
= So 0 £>gi 0 Cg 2 © CDg 3
for bond set {C, D] and with CRMT coefficients

B = AB.

Introducing these coefficients into Eq. (5.55) gives the minimized result for FCD

F CD = A ®BD © C ®ABC@ABCD
= A®C@BD@ABCD. (5.56)

Following the same procedure for function H AB, there results

H AB = (Afi/o) © (AB/,) © (ABfz) © (AB/ 3)
= (AB)(C © D) © (AB)(C © D) © (Afl)C © (Afl)C

= go © figi © Ag 2 © A5g 3 (5.57)
for bond set {A, B}. From Fig. 5.8b and Eq. (5.18), the CRMT g coefficients become

which, when introduced into Eq. (5.57), give the absolute minimum result

H AB = C©D©fl©A D
(5.58)