main.asm

采用TMS320VC5402实现一个16阶低通滤波器

         .title  "main-dsk"

***********************************************************************
* This programme aims for testing the dspvc5402 analogy loopback 											    *
***********************************************************************

		.include	"regs.h"
		.def	main
		.def	BRINT1_ISR
		.ref	init_5402
		.ref	init_McBSP
		.ref	init_AD50
		


***********************************************************************
* Declare the stack.  Size is determined by the linker option -stack. *
* The default value is 1K words.                                      *
***********************************************************************

stack:		.usect	".stack",100h

*=====================================================================*
*  				allocate data memory for data table				      *
*=====================================================================*

length      .set     0FFh				; data table of length FFh
	 	.sect	".table" 
		 
***********************************************************************
* 		VARIABLE AND GLOBAL FUNCTION DECLARATIONS   		    	  *
***********************************************************************

         .data

temp	 	.word	00000h			; temp storage
freq_scale	.word	00001h
ampl_scale	.word   07FFFh			; amplitude scaling factor 	
									; (default =1)
host_cmd	.word	00000h			; host cmd reg, init val: wait
  
            
           .bss    table,200h
           
***********************************************************************
* 		BEGINING OF EXECUTABLE CODE   		    	  				  *
***********************************************************************

         .text
main:      

*=====================================================================*
*  Init stack pointer.  Stack grows from high to low address	    *
*=====================================================================*

        STM      #stack+100h,SP 
		nop
		nop
		nop
		nop

*======================================================================*
*		Main code starts from here                                 *
*======================================================================*

		ssbx intm                      ; globally disable all interrupts
        	call init_5402
		call init_McBSP
		call init_AD50
	
        nop
        nop
        ssbx OVM                        ; OVM = 1 (saturate at overflow)
        ssbx FRCT                       ; ASM = 1 (shift left 1-bit)
        ssbx SXM 

        stm #McBSP1_DRR1,AR4            ; ar4 holds McBSP receive reg addr
    	stm #McBSP1_DXR1,AR5            ; ar5 holds McBSP xmit reg addr

       STM #table,AR7			
       STM #200h,BK			;200h循环缓冲区
          
*======================================================================*
*		Wait for host command						               *
*======================================================================*

*======================================================================*
*		Enable McBSP1 Tx and Rx and the interrupts			           *
*======================================================================*

EN_OUTPUT:

		stm  SPCR2,McBSP1_SPSA
		orm  #0001h,McBSP1_SPSD     ; enable xmtr
		nop
		nop
		stm  SPCR1,McBSP1_SPSA 
		orm #0001h,McBSP1_SPSD    ; enable rcvr
		nop
		nop

		
		stm  #7fffh,IFR                    	; clear pending interrupts, if any
		stm  #0400h,IMR				; unmask McBSP1 Rx interrupt
		NOP
		NOP
		rsbx intm 				; globally enable all interrupts
		
WAIT:
		NOP		
		NOP		
		bd WAIT		                        ; branch to idle loop
		nop
		nop
**************************************
* RECIEVER INTERRUPT SERVICE ROUTINE *
**************************************

BRINT1_ISR:
       
 
       	LD *AR4 ,A                
       	STL A,*AR7+% 
   	AND #0FFFEH,A     
        STLM A,*AR5 
        RETE
        nop
        nop
here:   b here

     .end