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Assembly Source File | 1992-08-07 | 24.3 KB | 441 lines

title 'Log-Log Audio Spectrum Analyzer' ;************************************************************************** ;* Motorola Austin DSP Operation June 06, 1991 * ;* * ;* * ALTHOUGH THE INFORMATION CONTAINED HEREIN, * * ;* * AS WELL AS ANY INFORMATION PROVIDED RELATIVE * * ;* * THERETO, HAS BEEN CAREFULLY REVIEWED AND IS * * ;* * BELIEVED ACCURATE, MOTOROLA ASSUMES NO * * ;* * LIABILITY ARISING OUT OF ITS APPLICATION OR * * ;* * USE, NEITHER DOES IT CONVEY ANY LICENSE UNDER * * ;* * ITS PATENT RIGHTS NOR THE RIGHTS OF OTHERS. * * ;* * ;* This program originally available on the Motorola DSP bulletin board. * ;* It is provided under a DISCLAMER OF WARRANTY available from * ;* Motorola DSP Operation, 6501 Wm. Cannon Drive W., Austin, Tx., 78735. * ;* * ;********************************************************************** ; Real time log-log scale spectrum analyzer program * ;********************************************************************** ; Source file name : aspec2.asm ; 0.0 Jan. 3 1990 ; 1.0 Mar. 23 1990 ; 1.1 Jul. 26 1990 - speed-up for windowing ; 1.2 Oct. 18 1990 - collapsed into single Goertzel sub. ; 2.0 Feb. 28 1990 - added interrupt driven input ; ; -This program will take in N samples from the DSP56ADC16 sigma delta ; converter and perform a DFT routine using Goertzel method. ; -The receive input buffer is filled under interrupt control ; -When the computations for the spectrum are completed, the input ; buffer (RXBUFF) is copied into D_IN and a new set of computations ; begin. During this time, RXBUFF continues to get new data samples,but ; this does not corrupt the buffer move because the oldeset sample is ; copied before the next input sample overwrites it. All other samples ; will have adequate time to be copied before changed by the input. ; -Results are sent to a PCM-56 DAC ; -The spectrum is viewed on a scope. ; ; Notes: 60, 0, -60, and -120 dB output reference levels ; DSP56001 REV C is required for SSI mixed length frame syncs ; Requires ADC16EVB modified for async SSI ;----------------------------------------------------------------------------- page 255,66,3,3,5 opt nomd,nomex,nocex BOOTMODE equ ROM ;1 == boot from ROM start equ $40 ;location of main routine ROMBASE equ $4000 ;load address of ROM - $8000 POINTS equ 2048 ;number of input data points($800) D_IN equ 0 ;location of input data table D_OUT equ POINTS ;location of output display table COS_TABL equ POINTS/2 ;sine and cosine table SIN_TABL equ POINTS/2+POINTS/4 BUF1 equ POINTS ;location for 1024 data buffer BUF2 equ POINTS+POINTS/2 ;location for 512 data buffer BUF3 equ POINTS+POINTS/2+POINTS/4 ;location for 256 data buffer WIN_TABL equ 0 ;location of Blackman_Harris window RXBUFF equ 2*POINTS ;location of input data ;---------------------------------------------------------------------------- ; ***** MEMORY MAP ***** ; -X- -Y- ; $1800 -------- ; $1000 RXBUFFER ; $0F00 ----- . ; $0E00 BUF3 . ; $0C00 BUF2 . ; $0A00 Polynomial Coefficients ; $0800 BUF1 $0800 D_OUT ; $0600 SINE Table ; $0400 COSINE Table ; $0000 D_IN $0000 Window Table ;---------------------------------------------------------------------------- ; MOTOROLA DSP56001 Internal I/O Addresses m_ipr equ $ffff ;Interrupt Prioroty Register m_bcr equ $fffe ;Bus Control Register m_sccr equ $fff2 ;SCI Clock Control Register m_scr equ $fff0 ;SCI Control Register m_tx equ $ffef ;SSI Tx Data Register m_rx equ $ffef ;SSI Rx Data Register m_sr equ $ffee ;SSI Status Register m_crb equ $ffed ;SSI Control Register A m_cra equ $ffec ;SSI Control Register B m_bdr equ $ffe4 ;Port-B Data Register m_bddr equ $ffe2 ;Port-B Data Direction Register m_pcc equ $ffe1 ;Port-C Control register IF BOOTMODE==1 ;*** if booting from ROM *** MSG 'Building Code for ROM Boot' ;-------------------------------------------------------------------------- ; RESET vector ; first, move the tables from ROM into data memory ;-------------------------------------------------------------------------- org p:0,p:ROMBASE ;RUN @ P:$0000, LOAD from P:$C000 GO move #$C000+(3*WIN_LOC),r0 ;points to start of tables in ROM move #0,r5 ;destination for tables in Y: do #Tab_Len,_table ;load all tables..., length <= $FFF do #3,_word ;3 bytes per word... move P:(R0)+,A2 ;get a byte from P:ROM rep #8 ;shift it into position... asr A ;...to form a 24-bit word _word move A1,y:(r5)+ ;move complete word into y:memory _table jmp <SPEC ELSE MSG 'Building Code for ADM execution' org p:$0C ENDIF ;------------------------------------- ; SSI RX Interrupt vector ;------------------------------------- ; *** org p:$000C,P: *** movep x:m_tx,y:(r1)+ ;input from ADC16 nop movep x:m_tx,y:(r1)+ ;input from ADC16 nop ;------------------------------------- ; SSI TX Interrupt vector ;------------------------------------- movep y:(r6)+,x:m_rx ;output to D/A PCM-56 nop movep y:(r6)+,x:m_rx ;output to D/A PCM-56 nop DUP $2C ;fill unused vectors w/ nops nop ENDM ;------------------------------------- ; Initialization ;------------------------------------- ;this code s/b @ P:$0040 SPEC movep #0,x:m_bcr ;set bcr to zero movec #0,sp ;init stack pointer movec #0,sr ;clear loop flag movep #0,x:m_pcc ;zero PCC to cycle it, reset peripherals ;----------------------------------------------------------------------- ; set the SCI to provide ADC16 clock ;----------------------------------------------------------------------- movep #$1000,x:m_sccr ;SCCR pattern for sclk= x16 baud rate movep #$2,x:m_scr ;SCR pattern for sclk= x16 baud rate ;----------------------------------------------------------------------- ; set the SSI to recieve ADC16's output ; and to transmit to the PCM56 using asynchronous, normal mode. ;----------------------------------------------------------------------- movep #$4107,x:m_cra ;CRA pattern for word length=16 bits ;xmit bit rate movep #$B1B0,x:m_crb ;CRB pattern for cont.clk,async,normal mode movep #$0001FF,x:m_pcc ;write PCC, enable peripherals ;-------------------------------------------------------------------------- ; Input sample rate is controlled by DSP56001 SCI via DSPADC16. ; Display rate is generated by DSP56001 (Fosc/512) ;-------------------------------------------------------------------------- move #D_OUT,r4 ;R4 for write into display buffer move r4,r6 ;R6 for read from display buffer move #RXBUFF,r1 ;R1 for write into RCV buffer move #POINTS/4-1,m4 ;both R4 & R6 use modulus addressing move m4,m6 ;MOD = buffer length = POINTS/2 move #POINTS-1,m1 ;...RCV BUFFER is also MOD addr. movep #$3000,x:m_ipr ;set SSI interrupt priority andi #$fc,MR ;unmask interrupts ;...after reset, Mx=$FFFF page ;--------------------------------------------------------------------------- ; ******************************** ; * MAIN PROGRAM ROUTINE * ; ******************************** ; ; The following registers have DEDICATED usage and should not be altered: ; R1 - input buffer write pointer M1 - POINTS - 1 ; R4 - display buffer write pointer M4 - POINTS/4 - 1 ; R6 - display buffer read pointer M6 - same as M4 ;--------------------------------------------------------------------------- ; get the oldest data in the input area and move it into the ; input buffer, shifting right 8-bits ( / 256 ) on the fly ;--------------------------------------------------------------------------- top move #D_IN,r0 ;pointer to input data buffer move #>$008000,x0 ;scale input data by 1/256 (>> 8) move #$0001,n1 move m1,m5 ;input will use mod. addressing here lua (r1)+n,r5 ;adjust pointer, move y:(r1),y1 ;get A/D converter oldest data mpy y1,x0,a ;and compute 1st output do #POINTS,_readin ;read in 2048 points, interruptable mpy y1,x0,a y:(r5)+,y1 a,x:(r0)+ ;shift, read, write _readin ;...I like it!.. move #-1,m5 ;restore linear addressing ;--------------------------------------------------------------------------- ; copy first 1024 points to BUF1 with a window function ; NOTE: data has been scaled by 1/256 during input ;--------------------------------------------------------------------------- move #WIN_TABL,r2 ;pointer to window in Y space move #2,n2 ;off-set register for every 2nd window move #D_IN,r0 ;pointer to data in X space move #D_IN+(POINTS/2)-1,r3 ;points to last input data point move #BUF1,r5 ;point to 1024-point buffer move #BUF1+(POINTS/2)-1,r7 ;points to end of output data buffer move x:(r0)+,x0 ;get 1st data point move y:(r2)+n2,y0 ;get 1st window value do #POINTS/4,wind1 ;do 512 pairs of points mpy x0,y0,a x:(r3)-,x0 ;apply window and get the sample mpy x0,y0,a a,x:(r5)+ ;apply window to last sample, store early sample move x:(r0)+,x0 ;get next early sample.. move a,x:(r7)- y:(r2)+n2,y0 ;store sample at end of buffer wind1 ;get next window value ;--------------------------------------------------------------------------- ; copy 512 points to BUF2 with a window function ; NOTE: samples are scaled up by a factor of 2 before storage ; automatic scaling provides the shift ;--------------------------------------------------------------------------- move #WIN_TABL,r2 ;pointer to window in Y space move #4,n2 ;off-set for every 4-th window point move #D_IN,r0 ;pointer to data in X space move #D_IN+(POINTS/4)-1,r3 ;points to last input data point move #BUF2,r5 ;point to 512 size buffer move #BUF2+(POINTS/4)-1,r7 ;points to end of output data buffer move x:(r0)+,x0 ;get first sample move y:(r2)+n2,y0 ;get first window value bset #9,SR ;Scaling mode 2; ASL--> XDB,YDB do #POINTS/8,wind2 ;do first 256 pairs of points mpy x0,y0,a x:(r3)-,x0 ;apply window, get end sample mpy x0,y0,a a,x:(r5)+ ;window end sample, store early sample move x:(r0)+,x0 ;scale end sample, get next early sample move a,x:(r7)- y:(r2)+n2,y0 ;store end sample, get next window value wind2 ;--------------------------------------------------------------------------- ; copy 256 points to BUF3 with a window function ; NOTE: data samples are scaled up by 2 bits before storage ; scaling mode provides one bit of shift automatically... ;--------------------------------------------------------------------------- move #WIN_TABL,r2 ;pointer to window in Y space move #8,n2 ;off-set for every 4-th window point move #D_IN,r0 ;pointer to data in X space move #D_IN+(POINTS/8)-1,r3 ;points to last input data point move #BUF3,r5 ;point to 512 size buffer move #BUF3+(POINTS/8)-1,r7 ;points to end of output data buffer move x:(r0)+,x0 move y:(r2)+n2,y0 ;get proper window value do #POINTS/16,wind3 ;do 128 pairs of points mpyr x0,y0,a x:(r3)-,x0 ;windowing asl a mpyr x0,y0,a a,x:(r5)+ ;windowing asl a x:(r0)+,x0 move a,x:(r7)- y:(r2)+n2,y0 ;store into input buffer wind3 ;--------------------------------------------------------------------------- ; Apply window to 2048 input data samples -- in place ; NOTE: data is scaled down by one bit before storage ;--------------------------------------------------------------------------- move #WIN_TABL,r7 ;pointer to window in Y space move #D_IN,r0 ;pointer to data start in X space move #D_IN+POINTS-1,r2 ;pointer to data end in X space bclr #9,SR ;turn scaling OFF bset #8,SR ;scale by ASR 1 bit do #POINTS/2,wind4 ;do first 1024 pairs of points move x:(r0),x0 y:(r7)+,y0 ;get start data and window value mpy x0,y0,a x:(r2),x0 ;...windowing...get end points mpy x0,y0,a a,x:(r0)+ ;store into input buffer move a,x:(r2)- wind4 bclr #8,SR ;turn scaling OFF ;--------------------------------------------------------------------- ; Place calibrated levels at start of the display table ; Levels 60, 0, -60, and -120.0 dB (15 dB/div on 8 div scope) ;--------------------------------------------------------------------- move #0.31143,a ; 60 dB level for trigger syncing clr b a,y:(r4)+ ; 0 dB level --> B neg a b,y:(r4)+ ; -60 dB level --> A asl a a,y:(r4)+ ;-120 dB level --> A move a,y:(r4)+ stitle 'main data processing loop' page ;---------------------------------------------------------------------------- ; Data Processing Routine (N point DFT using the Goertzel algorithm) ;---------------------------------------------------------------------------- move #SIN_TABL+4,r5 ;R5 points to sin Ymem table move #COS_TABL+4,r3 ;R3 points to cos Xmem table ;---------------------------------------------------------------------------- ; Run first 256-4 point DFT using the Goertzel algorithm ;---------------------------------------------------------------------------- move #D_IN,n2 ;n2 points to input data Xmem table move #POINTS/8-4,n3 ;run first 256-4 points DFT move #POINTS-1,n5 ;do 2048 point DFT jsr Goertzel ;---------------------------------------------------------------------------- ; next 128 point DFT using the Goertzel algorithm ;---------------------------------------------------------------------------- move #BUF1,n2 ;n2 points to input data Xmem table move #POINTS/16,n3 ;run next 128 point DFT move #POINTS/2-1,n5 ;do 1024 points DFT jsr Goertzel ;---------------------------------------------------------------------------- ; next 64 point DFT using the Goertzel algorithm ;---------------------------------------------------------------------------- move #BUF2,n2 ;n2 points to input data Xmem table move #POINTS/32,n3 ;run next 64 point DFT move #POINTS/4-1,n5 ;do 512 points DFT jsr Goertzel ;---------------------------------------------------------------------------- ; last 64 point DFT using the Goertzel algorithm ;---------------------------------------------------------------------------- move #BUF3,n2 ;n2 points to input data Xmem table move #POINTS/32,n3 ;run next 64 point DFT move #POINTS/8-1,n5 ;do 256 points DFT jsr Goertzel bset #14,x:m_crb ;enable SSI (TRE) interrupt jmp top ;do main program over again stitle 'Goertzel DFT Routine' page ;------------------------------------------------------------------------- ; Goertzel Algorithm for computing DFT ; solve for yr + yi = (x(n)+yr'*cosx-yi'*sinx) + i(yr'*sinx+yi'*cosx) ; ; on entry: n2 points to the input data buffer in Xmem ; n3 contains the number of output points ; n5 contains the number of input points ; r3 points to cosine table ; r5 points to sine table ; ;------------------------------------------------------------------------- Goertzel do n3,Goer_out ;run DFT move n2,r2 clr b y:(r3)+,x1 ;x1=cos(x) from table move b,x0 y:(r5)+,y1 ;y1=sin(x) from table move x:(r2)+,a ;a=x(n) ;x0=yr', y0=yi' do n5,Goer_in mac x0,x1,a b,y0 ;a=x(n)+cosx*yr' mac -y0,y1,a ;a=x(n)+cosx*yr'-sinx*yi' mpy x0,y1,b a,x0 ;b=sinx*yr' mac y0,x1,b x:(r2)+,a ;b=sinx*yr'+cosx*yi' Goer_in mac x0,x1,a b,y0 ;a=x(n)+cosx*yr' macr -y0,y1,a ;a=x(n)+cosx*yr'-sinx*yi' mpy x0,y1,b ;b=sinx*yr' macr y0,x1,b a1,x0 ;b=sinx*yr'+cosx*yi' ;------------------------------------------------------------------------- ; Convert to magnitude, in place, putting magnitude ;------------------------------------------------------------------------- convert mpy x0,x0,a b1,y0 ; A=yr**2, put b into y0 mac y0,y0,a #<$40,x0 ; A=yr**2+yi**2 move a1,y1 ; transfer sum of squares to Y move a0,y0 ;------------------------------------------------------------------------ ; Take a square root to get the resolution back into to 24 bits. ; Full Precision Square Root by Polynomial Approximation. ; y(y1:y0) = double precision (48 bit) positive input number ; b = 24 bit output root, x0 = guess, x1 = bit being tested ;------------------------------------------------------------------------ sqrt3 clr b x0,x1 ; init root and guess ; init bit to test do #23,endsqrt mpy -x0,x0,a ; square and negate the guess add y,a ; compare to double precision input tge x0,b ; update root if input >= guess tfr x1,a ; get bit to test asr a ; shift to next bit to test add b,a a,x1 ; form new guess move a,x0 ; save new guess endsqrt page ;--------------------------------------------------------------------- ; Log base 2 conversion routine. Converts the positive magnitude ; data to (log base 2)/32. ; See 56001 Manual for detail reference ;------------------------------------------------------------------------ ; log of zero fixup...uses -1 for the log of zero ;------------------------------------------------------------------------ move #>$000008,a cmp a,b #-0.6228,a ;for the log of zero use -120 dB jle <loga ;if argument is zero, force to max neg move m3,r7 ;m3 = -1 ($FFFF) rep #23 ;normalize to between .5 and 1.0 norm r7,b ;shift left and decrement r7 if needed move #pcoef,r0 ;point to poly. coefs. for log2 move b,x0 ;put normalized number in x0 mpyr x0,x0,a y:(r0)+,y0 ;x**2, get a1 mpy x0,y0,a a,x1 y:(r0)+,y0 ;a1*x, mv x**2, get a2 mac x1,y0,a y:(r0)+,y0 ;a2* x**2, get a0 add y0,a ;add in a0 asl a ;multiply by 4 asl a asl a ;shift out sign bit move r7,a2 ;new sign = characteristic rep #6 ;divide by 32, create sign bit asr a loga rnd a ;round result move a,y:(r4)+ ;update display table Goer_out ;***** END OF DO LOOP!!! ***** rts ;return from Goertzel subroutine ;------------------------------------------------------------------------ ; static data storage ;------------------------------------------------------------------------ IF BOOTMODE==1 ;*** if booting from ROM *** WIN_LOC set *-GO ;convince assembler to compute WIN_DAT ;...get all tables together nolist ;...at the end of the code in ROM include 'window1' ;NOTE: the order IS important include 'cosine' include 'sine' pcoef dc .9981958,-.3372223,-.6626105 ;start of polynomial coefficent table list Tab_Len equ *-WIN_DAT ;length of tables ELSE ;*** if testing in RAM *** nolist org y:WIN_TABL include 'window1' org y:COS_TABL include 'cosine' org y:SIN_TABL include 'sine' pcoef dc .9981958,-.3372223,-.6626105 ;start of polynomial coefficent table list ENDIF end SPEC