;*****************************************************************************
;  Function:	  uart.asm         
;  Version :	 1.00
;  Description:  uart
;
;  Copyright Texas instruments Inc, 2000

;*****************************************************************************
    .mmregs  

;	.global _sample_buff

;*****************************************************************************
        .def	 _int23     
        .global _t8251 ,_rend,_send  
         ;rend為接收完標志,send為發送完標志

dr8251  .set   8000h
cr8251  .set   8001h 
icr     .set   0ffech        
	.text                

_int23:  
      nop
      MAR  *,AR1 
      sst  #1,*+
      sst  #0,*+
      sar  ar0,*+
      sar  ar1,*+
      SAR  AR3,*+                             
      sar  ar4,*+
      SAR  AR5,*+
      sacl *+
      sach *+            ;以上為保護寄存器     

      
 ldp #0h 
       lar ar0,#0h       
      IN 60h,icr   
      nop      
      BIT 60h,13         ;測試INT2
      bcnd  SEND,NTC 
      
    ;  BIT 60h,12
    ;  bcnd  SEND,TC         

     ; lar ar5,61H         ;接收的數據量 
      
      
RECEIVE:  ldp #0h
          lar  ar3,6eh    ;啟動接收  

          mar *,ar3 

      
      IN  *+,dr8251 
      nop
            
      
      sar ar3,6eh   
      ;mar *,ar5
      ;mar *-
      ;sar ar5,61h 
      ;cmpr 0            ;判斷是否已經接收了10個數
      ;bcnd  next,ntc
      
      ;lar ar3,#(_rend)  ;rend=1 則往下執行 主程序
      ;mar *,ar3                    
    ;  splk #1h,*  
     ; splk #00ffh,63h 
       
      ;splk #0012h,60h 
      ;out  60H,icr
      
next:                            
           B end   
      
SEND:     
    
      BIT 60h,12         ;測試INT3
      bcnd  end,NTC 

      lar ar5,64H  ;發送的數據量   

      lar  ar3,6dH      ;啟動串口發送
      mar *,ar3 
      
      out  *+,dr8251 
      nop
      
      sar ar3,6dh   
      
      mar *,ar5
      mar *-
      sar ar5,64h 
      cmpr 0            ;判斷是否已經發送了20個數
      bcnd  end,ntc
      
      
      
                         
      lar ar3,#(_send)  ;send=1 則往下執行 主程序
      mar *,ar3                    
      splk #1h,*  
      splk #00ffh,63h 
      
      lar ar3,6cH
      SAR AR3,6dH    ;恢復t8251初始地址
      splk #001dh,60h 
      out  60H,icr
            
    ; ldp #0h

    ;  splk #00BBh,60h 
      
     ; LAR AR5,6FH 
      
     

     ; nop


    ;  out  60H,dr8251 
    ;  nop
    ;  nop
    ;  nop
     ; nop
     ; nop     
            

end: SPLK #003FH,ifr    
      in 62h,icr
      nop
      nop
      nop
      nop
      out 62h,icr
     
     
      MAR  *,AR1
      mar  *-   
      lacc *-,16
      add  *- 
      
	  LAR  AR5,*- 
	  nop
      LAR  AR4,*-
	  nop
      LAR  AR3,*-
	  nop       
	  lar  ar1,*
	  nop       
	  mar  *-
	  lar  ar0,*-
	  nop
	  lst #0,*-
      nop      
      lst #1,*
      nop
      clrc  intm
      ret
      
;	.endif
;end of file. please do not remove. it is left here to ensure that no lines of code are removed by any editor