對於序列信號001010, 選擇四位: 0010->0101->1010->0100->1000->0001->0010->...... 無重複狀態, 則選擇該種設計方案(若選擇三位會產生重複狀態).
由此, 得到狀態順序表.
狀態順序表 | ||||
CLK順序 | Q3 | Q2 | Q1 | Q0 |
0 | 0 | 0 | 1 | 0 |
1 | 0 | 1 | 0 | 1 |
2 | 1 | 0 | 1 | 0 |
3 | 0 | 1 | 0 | 0 |
4 | 1 | 0 | 0 | 0 |
5 | 0 | 0 | 0 | 1 |
6 | 0 | 0 | 1 | 0 |
由狀態順序表, 可以看出需要的序列信號由Q3端輸出.
根據狀態順序表, 再使電路具備自啓動功能, 有下述狀態表.
狀態表 | |||||||
Q3 | Q2 | Q1 | Q0 | Q3* | Q2* | Q1* | Q0* |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
0 | 0 | 0 | 1 | 0 | 0 | 1 | 0 |
0 | 0 | 1 | 0 | 0 | 1 | 0 | 1 |
0 | 0 | 1 | 1 | 0 | 1 | 1 | 0 |
0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 |
0 | 1 | 0 | 1 | 1 | 0 | 1 | 0 |
0 | 1 | 1 | 0 | 1 | 1 | 0 | 0 |
0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 |
1 | 0 | 1 | 0 | 0 | 1 | 0 | 0 |
1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 |
1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 |
1 | 1 | 0 | 1 | 1 | 0 | 1 | 0 |
1 | 1 | 1 | 0 | 1 | 1 | 0 | 1 |
1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
由於電路本身就是一個同步右移移位寄存器, 所以只需設計D0即可.
狀態激勵表 | ||||
Q3 | Q2 | Q1 | Q0 | D0 |
0 | 0 | 0 | 0 | 1 |
0 | 0 | 0 | 1 | 0 |
0 | 0 | 1 | 0 | 1 |
0 | 0 | 1 | 1 | 0 |
0 | 1 | 0 | 0 | 0 |
0 | 1 | 0 | 1 | 0 |
0 | 1 | 1 | 0 | 0 |
0 | 1 | 1 | 1 | 1 |
1 | 0 | 0 | 0 | 1 |
1 | 0 | 0 | 1 | 0 |
1 | 0 | 1 | 0 | 0 |
1 | 0 | 1 | 1 | 0 |
1 | 1 | 0 | 0 | 0 |
1 | 1 | 0 | 1 | 0 |
1 | 1 | 1 | 0 | 1 |
1 | 1 | 1 | 1 | 0 |
用2片74151和一片非門組成16選1數據選擇器, 以此實現D0的邏輯表達式.
根據上面的分析, 繪製電路的原理圖.