1. 卡諾圖
卡諾圖是化簡布林表示式的方法。
目的是減少數位系統中邏輯閘數目。
Gate-level minimization

3. 需要 2個Inverter和一個2輸入的OR gate ??
用最少數目的邏輯閘建構下列布林函數
需要 2個Inverter和一個2輸入的OR gate ??
一個2輸入的NAND gate

4. 布林代數運算容易嗎?
上式還能再簡化嗎?

5. 寫出F1及F2的真值表

7. 寫出F1的標準SOP表示式

8. 寫出F2的標準SOP表示式

9. 寫出F1的標準POS表示式

10. 寫出F2的標準POS表示式

11. 以布林代數簡化，常發生未達最簡式

12. Gate-level minimization refers to the design task of finding an optimal gate-level implementation of Boolean functions describing a digital circuit.

13. The Map Method The complexity of the digital logic gates
the complexity of the algebraic expression
Logic minimization
algebraic approaches: lack specific rules
the Karnaugh map
a simple straight forward procedure
a pictorial form of a truth table
applicable if the # of variables < 7
A diagram made up of squares
each square represents one minterm

14. Two-Variable Map A two-variable map four minterms
x' = row 0; x = row 1
y' = column 0;
y = column 1
a truth table in square diagram xy
x+y =
Fig. 3.2 Representation of functions in the map

15. A three-variable map eight minterms the Gray code sequence
any two adjacent squares in the map differ by only on variable
primed in one square and unprimed in the other
e.g., m5 and m7 can be simplified
m5+ m7 = xy'z + xyz = xz (y'+y) = xz

16. 練習題
Example 3-1
F(x,y,z) = S(2,3,4,5)
F = x'y + xy'

17. m0 and m2 (m4 and m6) are adjacent
m0+ m2 = x'y'z' + x'yz' = x'z' (y'+y) = x'z'
m4+ m6 = xy'z' + xyz' = xz' (y'+y) = xz'

18. 練習題
Example 3-2
F(x,y,z) = S(3,4,6,7) = yz+ xz'

19. Four adjacent squares 2, 4, 8 and 16 squares
m0+m2+m4+m6 = x'y'z'+x'yz'+xy'z'+xyz' = x'z'(y'+y) +xz'(y'+y) = x'z' + xz‘ = z'
m1+m3+m5+m7 = x'y'z+x'yz+xy'z+xyz =x'z(y'+y) + xz(y'+y) =x'z + xz = z

20. Example 3-3
F(x,y,z) = S(0,2,4,5,6)
F = z'+ xy'

21. Example 3-4 F = A'C + A'B + AB'C + BC express it in sum of minterms
find the minimal sum of products expression

22. Four-Variable Map The map 16 minterms
combinations of 2, 4, 8, and 16 adjacent squares

23. Example 3-5
F(w,x,y,z) = S(0,1,2,4,5,6,8,9,12,13,14)
F = y'+w'z'+xz'

24. Example 3-6 Simplify the Boolean function
F = ABC + BCD + ABCD + ABC

25. 練習題
利用布林代數運算及卡諾圖化簡下列布林函數

26. Implicants 含項:能使F為1的項
Prime implicant 質(主要的)含項:能使F為1的項,但是不能再合併
Essential prime implicant 必要項:沒有與其它prime implicant重疊的prime implicant

27. 練習題 F有4個 implicants: F有3個 prime implicants:
F沒有 essential prime implicants

28. Consider the simplified expression may not be unique
F = BD+B'D'+CD+AD = BD+B'D'+CD+AB
= BD+B'D'+B'C+AD = BD+B'D'+B'C+AB'

29. 3-4 Five-Variable Map
Map for more than four variables becomes complicated
five-variable map: two four-variable map (one on the top of the other)

30. Table 3.1 shows the relationship between the number of adjacent squares and the number of literals in the term.

31. Example 3-7
F = S(0,2,4,6,9,13,21,23,25,29,31)
F = A'B'E'+BD'E+ACE

32.  Another Map for Example 3-7

33. 3-5 Product of Sums Simplification
Approach #1
Simplified F' in the form of sum of products
Apply DeMorgan's theorem F = (F')'
F': sum of products => F: product of sums
Approach #2: duality
combinations of maxterms (it was minterms)
M0M1 = (A+B+C+D)(A+B+C+D') = (A+B+C)+(DD') = A+B+C

34. Example 3-8 F = S(0,1,2,5,8,9,10) F' = AB+CD+BD'
Apply DeMorgan's theorem; F=(A'+B')(C'+D')(B'+D)
Or think in terms of maxterms

35. Gate implementation of the function of Example 3-8

36. Consider the function defined in Table 3.2.
In sum-of-minterm:
In sum-of-maxterm:
Taking the complement of F

37. Consider the function defined in Table 3.2.
Combine the 1’s:
Combine the 0’s :

38. 3-6 Don't-Care Conditions
The value of a function is not specified for certain combinations of variables
BCD; : don't care
The don't care conditions can be utilized in logic minimization
can be implemented as 0 or 1
Example 3-9
F (w,x,y,z) = S(1,3,7,11,15)
d(w,x,y,z) = S(0,2,5)

39. Also apply to products of sum
F = yz + w'x'; F = yz + w'z
F = S(0,1,2,3,7,11,15) ; F = S(1,3,5,7,11,15)
either expression is acceptable
Also apply to products of sum

40. Two graphic symbols for a NAND gate

41. Two-level Implementation
two-level logic
NAND-NAND = sum of products
Example: F = AB+CD
F = ((AB)' (CD)' )' =AB+CD
Fig. 3-20
Three ways to implement
F = AB + CD