【正文】
部的 node,另外以 directed arcs 相連接,這些 arc 代表訊號的變化,因此 SG 遠比 STG 複雜,但在可以用在電路合成 (synthesis)。 解決的方法可有: (1) 增加一個 delay element:將 hazard 隱藏在 delay 之中。 S LO Wabcacabbcabcacabbc (s low ) 14. (6%)Draw Karnaugh maps to explain static1 hazard and dynamic10 hazard. (pp95) (1) static1 hazard 如果 state 依照 12,13,15,14 的順序來走,則 state 14 的 output 邏輯值應(yīng)該維持在 1,但實際上由於 15 的 1 是由 d 的值通過 OR gate 得來,而 14 的 1 是由 bamp。 (2) dynamic10 hazard 會發(fā)生在 4,6,2,0 的 state transition flow,在 state 4 會自然轉(zhuǎn)換到 state 6,此時如果將 b 降為 0 會進入 state 2,在自然轉(zhuǎn)換到 state 0, output 也應(yīng)該由 1變?yōu)?0,但在 state 6 時會使得 bamp。 15. (4%)Draw two possible variable z states’ implementation templates using (simple) state holding elements.(pp 96) (1)使用 SR latch (2)使用 Celement 16. (7%)Assume variable z’ s set logic and reset logic is zset = ab and zreset=b’ c’ ,respectively. Draw the circuit in gatlevel, and show implementations in dynamic CMOS and static CMOS.(pp 100) (1) dynamic CMOS implementation (2) static CMOS implementation 17. (6%)Explain the six characteristics of STG: 1bounded, liveness, consistent state assignment, persistency, and plete state coding. (pp 88) (1) Input free choice: The selection among alternatives must only be controlled by mutually exclusive inputs. (2) 1bounded: There must never be more than one token in a place. (3) Liveness: The STG must be free from deadlocks. (4) Consistent state assignment: The transitions of a signal must strictly alternate between _ and _ in any execution of the STG. (5) Persistency: If a signa