.module keypad.c
	.area text(rom, con, rel)
	.dbfile C:\work\mega128\mix_exp\keypad.c
	.dbfunc e scan_key _scan_key fc
;          shift -> R22,R23
;              i -> R10
;           temp -> R12
	.even
_scan_key::
	xcall push_gset4
	.dbline -1
	.dbline 6
; #include <iom128v.h>
; /*鍵盤掃描函數,沒有鍵按下返回0x7f*/
; /*如果shift按下，返回值最高位為1*/
; extern void delay_ms(unsigned int time);
; unsigned char scan_key(void)
;    {
	.dbline 8
;     unsigned char i,temp;
;     unsigned shift=0;
	clr R22
	clr R23
	.dbline 9
;     DDRB=0x0f;	
	ldi R24,15
	out 0x17,R24
	.dbline 10
; 	PORTB=0xff;	  
	ldi R24,255
	out 0x18,R24
	.dbline 11
;     for (i=0;i<4;i++)
	clr R10
	xjmp L5
L2:
	.dbline 12
;         {
	.dbline 13
;          PORTB=~(1<<i); //鍵盤線掃描
	ldi R16,1
	mov R17,R10
	xcall lsl8
	mov R2,R16
	com R2
	out 0x18,R2
	.dbline 14
;          delay_ms(5);   //等待低電平穩定
	ldi R16,5
	ldi R17,0
	xcall _delay_ms
	.dbline 15
;          temp=PINB&0xf0;//讀取鍵盤掃描信號,屏蔽低四位
	in R24,0x16
	andi R24,240
	mov R12,R24
	.dbline 16
;          if ((PIND&0x20)==0) temp|=01;//檢查shift鍵
	sbic 0x10,5
	rjmp L6
	.dbline 16
	ori R24,1
	mov R12,R24
L6:
	.dbline 17
;          if (temp!=0xf0)//如果有鍵按下，延時10ms消抖
	mov R24,R12
	cpi R24,240
	brne X1
	xjmp L8
X1:
	.dbline 18
;             {           //本程序用display代替10ms延時,
	.dbline 19
;              delay_ms(5); //可消除顯示抖動
	ldi R16,5
	ldi R17,0
	xcall _delay_ms
	.dbline 20
;              temp=PINB&0xf0;//再讀鍵盤
	in R24,0x16
	andi R24,240
	mov R12,R24
	.dbline 21
;              if ((PIND&0x20)==0) //檢查shift鍵
	sbic 0x10,5
	rjmp L10
	.dbline 22
;                 {
	.dbline 23
;                  temp|=01;
	ori R24,1
	mov R12,R24
	.dbline 24
;                  shift=1;
	ldi R22,1
	ldi R23,0
	.dbline 25
;                 }
L10:
	.dbline 26
;              if (temp!=0xf0)
	mov R24,R12
	cpi R24,240
	brne X2
	xjmp L12
X2:
	.dbline 27
;                 {
	.dbline 28
;                  temp&=0xf0;
	andi R24,240
	mov R12,R24
	.dbline 29
;                  switch (temp) //計算鍵值
	mov R20,R24
	clr R21
	cpi R20,176
	ldi R30,0
	cpc R21,R30
	breq L18
	ldi R24,176
	ldi R25,0
	cp R24,R20
	cpc R25,R21
	brlt L22
L21:
	cpi R20,112
	ldi R30,0
	cpc R21,R30
	breq L17
	xjmp L14
L22:
	cpi R20,208
	ldi R30,0
	cpc R21,R30
	breq L19
	cpi R20,208
	ldi R30,0
	cpc R21,R30
	brlt L14
L23:
	cpi R20,224
	ldi R30,0
	cpc R21,R30
	breq L20
	xjmp L14
X0:
	.dbline 30
;                      {
L17:
	.dbline 31
; 				      case 0x70:temp=15-(3-i)*4;break;
	ldi R17,3
	sub R17,R10
	ldi R16,4
	muls R16,R17
	ldi R24,15
	mov R12,R24
	sub R12,R0
	.dbline 31
	xjmp L15
L18:
	.dbline 32
;                       case 0xb0:temp=14-(3-i)*4;break;
	ldi R17,3
	sub R17,R10
	ldi R16,4
	muls R16,R17
	ldi R24,14
	mov R12,R24
	sub R12,R0
	.dbline 32
	xjmp L15
L19:
	.dbline 33
;                       case 0xd0:temp=13-(3-i)*4;break;
	ldi R17,3
	sub R17,R10
	ldi R16,4
	muls R16,R17
	ldi R24,13
	mov R12,R24
	sub R12,R0
	.dbline 33
	xjmp L15
L20:
	.dbline 34
;                       case 0xe0:temp=12-(3-i)*4;break;
	ldi R17,3
	sub R17,R10
	ldi R16,4
	muls R16,R17
	ldi R24,12
	mov R12,R24
	sub R12,R0
	.dbline 34
	xjmp L15
L14:
	.dbline 35
;                       default:temp=0x7f;					 
	ldi R24,127
	mov R12,R24
	.dbline 36
;                       }
L15:
	.dbline 37
;                  if (shift==1) temp|=0x80; 
	cpi R22,1
	ldi R30,0
	cpc R23,R30
	brne L24
	.dbline 37
	mov R24,R12
	ori R24,128
	mov R12,R24
L24:
	.dbline 38
;                  return temp;
	mov R16,R12
	xjmp L1
L12:
	.dbline 40
;                  }		 
;        	     }
L8:
	.dbline 41
	ldi R24,255
	out 0x18,R24
	.dbline 42
L3:
	.dbline 11
	inc R10
L5:
	.dbline 11
	mov R24,R10
	cpi R24,4
	brsh X3
	xjmp L2
X3:
	.dbline 43
;          PORTB=0xff;	 
;         }
;     return 0x7f;			 
	ldi R16,127
	.dbline -2
L1:
	xcall pop_gset4
	.dbline 0 ; func end
	ret
	.dbsym r shift 22 i
	.dbsym r i 10 c
	.dbsym r temp 12 c
	.dbend
	.dbfunc e keypad _keypad fc
;          temp1 -> R20
;          temp2 -> R22
	.even
_keypad::
	xcall push_gset2
	.dbline -1
	.dbline 46
;     }
; unsigned char keypad(void)
;     {
	.dbline 48
; 	 unsigned char temp1,temp2;
; 	 temp1=scan_key();
	xcall _scan_key
	mov R20,R16
	.dbline 49
; 	 if (temp1==0x7f) return 0x7f;
	cpi R16,127
	brne L27
	.dbline 49
	ldi R16,127
	xjmp L26
L27:
L29:
	.dbline 51
; 	 do
; 	   temp2=scan_key();
	xcall _scan_key
	mov R22,R16
L30:
	.dbline 52
; 	 while (temp1==temp2);
	cp R20,R22
	breq L29
	.dbline 53
; 	 return temp1;	 
	mov R16,R20
	.dbline -2
L26:
	xcall pop_gset2
	.dbline 0 ; func end
	ret
	.dbsym r temp1 20 c
	.dbsym r temp2 22 c
	.dbend