原创 IO键盘扫描次数之分析

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IO键盘扫描次数之分析 (hotpower)

hotpower 发表于 2003-9-7 06:13 EMC 单片机 ←返回版面    

1。在“独占式”键盘中，若采用管脚中断，故在主程序中不需扫描。
当然若非中断方式，则N个键需N次扫描(不算一次读入)
2。在“双向双次”键盘“扫描”技术中，由于行列扫描变换一次，故只需2次。
3。在行扫描中，可分为行列式和组合式
   在“行列式”键盘中(不算双向)，扫描次数为行列中的最小值。
   在“组合式”键盘中，最小扫描次数为IO个数-1。
即：四线6键，五线10键，六线15键，七线21键，八线28键
   在四线 6键中，扫描次数为3次
   在五线10键中，扫描次数为4次
   在六线15键中，扫描次数为5次
   在七线21键中，扫描次数为6次
   在八线28键中，扫描次数为7次
例：在八线28键中，设8线K1..K8
    组合为：K1K2,K1K3,K1K4,K1K5,K1K6,K1K7,K1K8
                K2K3,K2K4,K2K5,K2K6,K2K7,K2K8
                     K3K4,K3K5,K3K6,K3K7,K3K8
                          K4K5,K4K6,K4K7,K4K8
                               K5K6,K5K7,K5K8
                                    K6K7,K6K8
                                         K7K8
八线最大扫描：发K1,收K2,K3,K4,K5,K6,K7,K8
             发K2,收K1,K3,K4,K5,K6,K7,K8
             发K3,收K1,K2,K4,K5,K6,K7,K8
             发K4,收K1,K2,K3,K5,K6,K7,K8
             发K5,收K1,K2,K3,K4,K6,K7,K8
             发K6,收K1,K2,K3,K4,K5,K7,K8
             发K7,收K1,K2,K3,K4,K5,K6,K8
             发K8,收K1,K2,K3,K4,K5,K6,K7
八线最小扫描：发K1,收K2,K3,K4,K5,K6,K7,K8
             发K2,收K1,K3,K4,K5,K6,K7,K8
             发K3,收K1,K2,K4,K5,K6,K7,K8
             发K4,收K1,K2,K3,K5,K6,K7,K8
             发K5,收K1,K2,K3,K4,K6,K7,K8
             发K6,收K1,K2,K3,K4,K5,K7,K8
             发K7,收K1,K2,K3,K4,K5,K6,K8
同理：
四线最小扫描：发K1,收K2,K3,K4
             发K2,收K1,K3,K4
             发K3,收K1,K2,K4
五线最小扫描：发K1,收K2,K3,K4,K5
             发K2,收K1,K3,K4,K5
             发K3,收K1,K2,K4,K5
             发K4,收K1,K2,K3,K5
六线最小扫描：发K1,收K2,K3,K4,K5,K6
             发K2,收K1,K3,K4,K5,K6
             发K3,收K1,K2,K4,K5,K6
             发K4,收K1,K2,K3,K5,K6
             发K5,收K1,K2,K3,K4,K6
七线最小扫描：发K1,收K2,K3,K4,K5,K6,K7
             发K2,收K1,K3,K4,K5,K6,K7
             发K3,收K1,K2,K4,K5,K6,K7
             发K4,收K1,K2,K3,K5,K6,K7
             发K5,收K1,K2,K3,K4,K6,K7
             发K6,收K1,K2,K3,K4,K5,K7
由此可知：“组合式”键盘扫描次数较多，但相应的键数也越多。

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(文章推荐人：sparkstar)