system.asm

SPBA01B是由凌阳公司开发的可级连的单片I0、总线扩展芯片。它具有使用简单、扩展能力强、性价比高的特点。本程序实现了如何利用SPBA01B来对SPCE061A进行IO扩展。

//////////////////////////////////////////////////////////////////
// Function: System commander                     
// 	Service for H/W, keyboard scan
// Input: None
// Output: None

// Functions:
//	(In Assembly view)
// 	call F_System_Initial; 
//	(In C language view)
// 	System_Initial(); 
//////////////////////////////////////////////////////////////////

.include resource.inc;
.include hardware.inc;
.external F_SP_Read_XP0;
.CODE
.public _System_Initial;
.public	F_System_Initial;
_System_Initial: .PROC
F_System_Initial:
	
		call	F_User_Init_IO;			//	
		R1 = 0							// The interrupt is controlled by user
		[P_INT_Ctrl] = R1				//
		retf;
		.ENDP;
F_User_Init_IO:
		R1 = 0x00F0;
        [P_IOA_Dir] = R1;                    // Port A15- A8: input(FL)/output(OL)
        [P_IOA_Data] = R1;                   // Port A7 - A4: 高电平输出
        R1 = 0xFFF0;                         // Port A3 - A0: 下拉输入
        [P_IOA_Attrib] = R1;                 //      

   		R1 = 0xFFFF;                         //
 	    [P_IOB_Dir] = R1;                    //高电平输出
        [P_IOB_Data] = R1;                   //
        [P_IOB_Attrib] = R1;                 //

        retf;         

.public F_SP_KeyScan;
.public _SP_KeyScan;
_SP_KeyScan: .proc
F_SP_KeyScan:
		//call F_SP_Read_XP0;
		r1=[P_IOA_Data];
		r1&=0x0007;
		retf;
		.endp