loopcontrol.asm

320SC的datasheet资料

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************************************************************************
**  File Name:    LoopControl.asm
**  Part Number:  TLV320AIC10/11EVM-SW-0010
************************************************************************
**  Copyright (c) Texas Instruments, Inc. 2000
************************************************************************
**
**  Release History:
**     Version      Date          Engr          Description
**      1.00     10-11-2000    Wendy X Fang   Original Release
**
************************************************************************
**
**  Function: 
**     This program has the following two functions:
**     (1) control main loop repeat rate, here is equals to 10KHz
**         (using time0 to control and where
**               =CPUCLKFreq/(TDDR+1)/(PRD+1)=50M/3125=16KHz)
**     (2) flash XF pin at 1hz rate to indicate the main loop is running
**         (which can also be called DSP safety checking and indicating).
**
************************************************************************
**  References:
**  	(1) TMS320C54x DSP, CPU and Peripheral (SPRU131)
************************************************************************

      .global     _LoopControl

************************************************************************
** Include Statements
************************************************************************
      .include	MMRegs.h

************************************************************************
**  Varaible & Initialization
************************************************************************
           .global  LoopCount
Sparee     .usect   ".variable", 5
LoopCount  .usect   ".variable", 1  ; main loop counter (system var)
           .ref      _DCSICount
           .ref      _DCSIConfig
           .ref      _MasterCRValues
           
************************************************************************
**  Function Routine
************************************************************************
_LoopControl:
      NOP
      
******* DCSI is used for the configuration 
*******   of AIC10 device control registers   
      NOP
      LD    *(_DCSIConfig), A        ; check if DCSI config flag is on 
      BC    LoopWait0, AEQ          ; no, skip
      NOP                           ; otherwise
      STM   SPCR1,  McBSP1_SPSA     ; register subaddr of SPCR1
      STM   #4020h, McBSP1_SPSD     ; McBSP1 recv = left-justify
                                    ; RINT generated by frame sync
      STM   SPCR2,  McBSP1_SPSA     ; register subaddr for SPCR2
                                    ; XINT generated by frame sync
      STM   #0020h, McBSP1_SPSD     ; McBSP1 Tx = FREE(clock stops 
                                    ; to run after SW breakpoint
      
      LD     *(_DCSICount), A       ; check if DCSI in process
      BC     LoopWait, AGT          ; yes, skip
                                    ; otherwise
      ST     #0, *(_DCSICount)      ; clear DCSICount
      STM    #0xFFFF, IFR           ; clear interrupt flags
      STM    SPCR2, McBSP1_SPSA     ; enable McBSP1 TX for DCSI
      LDM    McBSP1_SPSD,A
      OR     #0x0001, A
      STLM   A, McBSP1_SPSD
      RPT    #7
      NOP      
      LD     *(_MasterCRValues), A  ; load master CR1 value
      STLM   A, McBSP1_DXR1
      STM    #0xFFFF, IFR
      STM    #0x0800, IMR           ; enable McBSP1 TX interrupt      
      NOP 
      B      LoopWait
      NOP
      
LoopWait0:
      NOP
      STM   SPCR1,  McBSP1_SPSA     ; register subaddr of SPCR1
      STM   #4000h, McBSP1_SPSD     ; McBSP1 recv = left-justify
                                    ; RINT generated by frame sync
      STM   SPCR2,  McBSP1_SPSA     ; register subaddr for SPCR2
                                    ; XINT generated by frame sync
      STM   #0000h, McBSP1_SPSD     ; McBSP1 Tx = FREE(clock stops 
                                    ; to run after SW breakpoint
      
      STM    SPCR2, McBSP1_SPSA     ; disable McBSP1 TX for DCSI
      LDM    McBSP1_SPSD,A
      AND    #0xFFFE, A
      STLM   A, McBSP1_SPSD
      RPT    #7
      NOP
      STM    #0xFFFF, IFR           ; clear interrupt flags
*      STM    #0x0010, IMR
      NOP

******* Wait for Starting Next Loop *******
LoopWait:                           ; wait for timer0 return to zero
      NOP
      LDM   IFR, A                  ; load interupt flag
      AND   #0x0008, A              ; mask out timer0 intr flag
      BC    LoopWait, AEQ           ; check if tim0 intr occured
      NOP                           ; no:  waiting
      OR    #0x0008, A              ; yes: clear timer0 interrupt flag
      STLM  A, IFR                  ; 
      LD    #LoopCount, DP          ; set DP to the page having LoopCount
      NOP
      NOP

****** Toggle/Flash XF at Frequency 1Hz *******
      ADDM  #1, LoopCount           ; increase LoopCounter by 1
      LD    LoopCount, A
      SUB   #8000, A                ; t=8000*2*(3125/50M)=1sec
      BC    LoopEnd, ALT            ; if not 1/2t, wait for mext loop 
      NOP                           ; else: toggle XF
      NOP

      ST    #0, LoopCount           ; reset LoopCount
      LDM   ST1, A                  ; check XF status: load ST1
      AND   #0x2000, A              ;     & mask out XF
      BC    SetXF, AEQ              ; if XF=0, to set XF=1
      NOP
      NOP
      RSBX  XF                      ; else (XF=1), to set XF=0
      B     LoopEnd
      NOP
SetXF:
      NOP
      SSBX  XF
      NOP
LoopEnd:
      NOP
      RETD                          ; return
      NOP
      NOP
	
      .end

************************************************************************
**  End of File -- LoopControl.asm
************************************************************************