74161功能表和引脚图
时间: 2023-07-10 15:04:52 浏览: 3553
74161是一个4位二进制同步计数器,具有清零和加载功能。以下是其功能表和引脚图:
**功能表:**
| CP | LD | CLR | QA | QB | QC | QD |
| --- | --- | --- | --- | --- | --- | --- |
| L | X | X | 0 | 0 | 0 | 0 |
| ↑ | L | X | 0 | 0 | 0 | 0 |
| ↑ | ↑ | X | 0 | 0 | 0 | 0 |
| ↑ | ↑ | L | 0 | 0 | 0 | 0 |
| ↑ | ↑ | ↑ | 1 | 0 | 0 | 0 |
| ↑ | ↑ | ↑ | 0 | 1 | 0 | 0 |
| ↑ | ↑ | ↑ | 0 | 0 | 1 | 0 |
| ↑ | ↑ | ↑ | 0 | 0 | 0 | 1 |
- CP:时钟输入
- LD:并行加载输入
- CLR:清零输入
- QA-QD:计数器的四个输出位
**引脚图:**
```
+---+--+---+
CP ----| U |---- QA
LD ----| |---- QB
CLR ---| 74161 |---- QC
-| |-+-- QD
-| | |
-|CLR/LOAD\ CP|-+
-| UP |-+
-| | |
-| QA |-|
-| QB |-+-- Parallel Load Inputs
-| QC |-|
-| QD |-+
+-----------+
```