key.asm

来自「给出了W29C040的驱动子程序」· 汇编 代码 · 共 26 行

.include   hardware.inc

.DEFINE C_DebounceCnt	6;  

.ram
.public  Key_Buff; 
.public  Key_Debounce; 
.public  Key_Strobe
.var    Key_Buff;           //本次键值暂存单元
.var    Key_Debounce;       //计数单元
.var    Key_Strobe

.code  
.public  _KeyScan;
_KeyScan: .proc
         r4=[P_IOA_Data]
       //  r4&=0x0007
       	 r4&=0x0003
         jnz F_SomeKeyIsPressed
         r1=0x0000
         [Key_Buff]=r1
         [Key_Strobe]=r1
         retf

 F_SomeKeyIsPressed:    
         r1=[Key_Buff]    //读上次键值