一、?設計目的：
1、?了解數字波形產生的原理；
2、?學習用DSP產生各種波形的基本方法和步驟；
3、?掌握DSP與D/A轉換器接口的使用。
二、?設計設備
計算機、DSP仿真器、ZSEED-DTK6713實驗箱、20M示波器
三、?設計原理
波形產生是DSP的重要應用之一。而正弦信號發生器的設計則是波形產生應用的一個重要方面，它在通信領域有著廣泛的應用。
通常有兩種方法可以產生正弦波，分別為查表法和泰勒級數展開法。
查表法是通過查表的方式來實現正弦波，主要用于對精度要求不很高的場合。
泰勒級數展開法是根據泰勒展開式進行計算來實現正弦信號，它能精確地計算出一個角度的正弦和余弦值，且只需要較小的存儲空間。
本次主要用泰勒級數展開法來實現正弦波信號。
產生正弦波的算法
正弦函數和余弦函數可以展開成泰勒級數，其表達式：
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取泰勒級數的前5項，得近似計算式：
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遞推公式：
sin(nx) = 2cos(x)sin[(n-1)x]-sin[(n-2)x]
cos(nx) = 2cos(x)sin[(n-1)x]-cos[(n-2)x] ??
由遞推公式可以看出，在計算正弦和余弦值時,需要已知cos(x)、sin(n-1)x、sin(n-2)x和cos(n-2)x。
為了減少使用的存儲器，可以采用正弦信號的對稱性，復制90～180度的正弦值和180～360度的正弦值。
余弦信號的產生同樣可以采用多種方法產生。一是采用公式計算得到，二是采用正弦信號變換得到。
方波信號產生可以通過輪流輸出兩個不同大小的數值通過A/D轉換得到。
四、?設計內容
?本設計題目以TMS320C54x DSP為目標器件，設計并實現基于迭代法的“正弦序列生成”算法及其DSP程序。
設計步驟：
1、?熟悉正弦信號發生器的算法以及在DSP系統的實現
2、?熟悉A/D轉換的原理及實驗箱的鏈接
3、?掌握A/D轉換的程序的編寫
4、?編寫DSP的正弦信號發生器的程序
5、?編寫定時程序產生100HZ、1KHZ、10KHZ的正弦、余弦以及100K、1M的方波信號，每種類型的波形單周期360個點。
6、?編寫按鍵程序，控制輸出。用三個撥碼開關對DSP進行輸入，輸入的0～7對應的8種不同的波形。
7、?用示波器觀察各個波形
8、?分析波形失真的原因。
五、?實驗步驟
1. 熟悉本實驗原理。
2. 閱讀本實驗樣例程序。
3.?依次連接主板上的PC10、PC11、TP32到PC15、PC16、GND；依次連接主板上的PC13、PC14、M58到插板上的DJ0、DJ1、S12。
4. 將計算機與ZSEED-DTK6713實驗箱通過并口P1相連。
5. 運行CCS軟件客戶軟件\DSP程序\test19，通過插板上的JP1，JP2，JP3來選擇不同的波形。
6. 用示波器觀察DA0的輸出波形。
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六、設計的硬件結構框圖
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七、?實驗代碼
???先計算0～45°（間隔為0.5°）的sin和cos值，在利用sin2a=2sina*cosa求出sin值（間隔為1°）。然后，通過復制，獲得0～359°的正弦值。重復向PA口輸出，便可得到正弦波。
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? .mmregs
.global main
.def start
.ref d_xs,d_sinx,d_xc,d_cosx,sinx,cosx
sin_x: ????.usect "sin_x",360
cos_x: ????.usect "cos_x",360
fangbo: ?.usect "fangbo",360
STACK: ????.usect "STACK",10H
k_theta???.set 286
TIM0 .set 0024H
PRD0 .set 0025H
TCR0 .set 0026H
PA ?? .set 0100H


.text
start: ????
?;產生正弦波數據
???????STM ?????k_theta,AR0
???????STM ?????#0,AR1
???????STM ?????#sin_x,AR6
???????STM ?????#90,BRC
???????RPTB ? loop1-1
???????LDM ?????AR1,A
???????LD ??? #d_xs,DP
???????STL ?????A,@d_xs
???????STL ?????A,@d_xc
???????CALL ? sinx
???????CALL ? cosx
???????LD ??? #d_sinx,DP
???????LD ??? @d_sinx,16,A
???????MPYA ? @d_cosx
???????STH ?????B,1,*AR6+
???????MAR ?????*AR1+0
loop1:?STM ????#sin_x+89,AR7
???????STM ?????#88,BRC
???????RPTB ? loop2-1
???????LD ??? *AR7-,A
???????STL ?????A,*AR6+
loop2: ???STM ?????#179,BRC
???????STM ?????#sin_x,AR7
???????RPTB ? loop3-1
???????LD ??? *AR7+,A
???????NEG ?????A
???????STL ?????A,*AR6+
loop3:STM ???#sin_x+89,AR6
???STM ?????#cos_x,AR7
?????????STM ?????#269,BRC ????????????
?????????RPTB ? lcos-1 ?????????
?????????LD ??? *AR6+,A
???????STL ?????A,*AR7+
lcos: ???STM ?????#sin_x,AR6
??????STM ?????#89,BRC ????????????
?????????RPTB ? loop4-1 ?????????
?????????LD ??? *AR6+,A
???????STL ?????A,*AR7+
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;產生方波數據
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loop4: STM ??#fangbo,AR6
???????STM ?????#179,BRC ????????????
??????? RPTB ? ?lfangbo-1 ?????????
??????? LD ??? ?#7FFFH,A
???????STL ?????A,*AR6+
lfangbo:
STM ?????#179,BRC ????????????
??????? RPTB ? ?main-1 ?????????
??????? LD ??? ?#0H,A
???????STL ?????A,*AR6+
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main: ?
STM ? #0,SWWSR
STM #STACK+10H,SP
STM #3FA0H,PMST
STM #0010H,TCR0
STM #0260H,TCR0
STM #0008H,IFR
STM #0008H,IMR
RSBX INTM
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PORTR ? PA,*AR2
??????
?????? LD *AR2,A
?????? AND #01B,A
?????? BC fangbo_1m,ANEQ
?????? LD *AR2,A
?????? AND #010B,A
?????? BC fangbo_100k,ANEQ
?????? LD *AR2,A
?????? AND #0100B,A
?????? BC sin_10k,ANEQ
?????? LD *AR2,A
?????? AND #01000B,A
?????? BC sin_1k,ANEQ
?????? LD *AR2,A
?????? AND #010000B,A
?????? BC sin_100,ANEQ
?????? LD *AR2,A
?????? AND #0100000B,A
?????? BC cos_10k,ANEQ
?????? LD *AR2,A
?????? AND #01000000B,A
?????? BC cos_1k,ANEQ
?????? LD *AR2,A
?????? AND #10000000B,A
?????? BC cos_100,ANEQ
??????
end: B end
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fangbo_1m:
STM #10,TIM0
STM #10,PRD0
STM #fangbo,AR3
B main
fangbo_100k:
STM #110,TIM0
STM #110,PRD0
STM #fangbo,AR3
B main
sin_10k:
STM #2,TIM0
STM #2,PRD0
STM #sin_x,AR3
B main
sin_1k:
STM #30,TIM0
STM #30,PRD0
STM #sin_x,AR3
B main
sin_100:
STM #306,TIM0
STM #306,PRD0
STM #sin_x,AR3
B main
cos_10k:
STM #2,TIM0
STM #2,PRD0
STM #sin_x,AR3
B main
cos_1k:
STM #30,TIM0
STM #30,PRD0
STM #sin_x,AR3
B main
cos_100:
STM #306,TIM0
STM #306,PRD0
STM #sin_x,AR3
B main

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;定時器中斷輸出
TINT_T0:
??????? STM ???? #1,AR0
??????? STM ????? #360,BK ??????

loop: PORTW *AR3+0%,PA
B loop
RETE
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sinx: ??????????????????????????????
??????? .def ?d_xs,d_sinx
???????
??????? .data
table_s ?? .word 01c7h ??????????;c1=1/(8*9)
??????? .word 030bh ??????????;c2=1/(6*7)
??????? .word 0666h ??????????;c3=1/(4*5)
??????? .word 1556h ??????????;c4=1/(2*3)
coef_s ? .usect ??"coef_s",4
d_xs ?? .usect ??"sin_vars",1
squr_xs ?? .usect ??"sin_vars",1
temp_s .usect ??"sin_vars",1
d_sinx .usect ??"sin_vars",1
l_s ??? .usect ??"sin_vars",1
???????.text
???????SSBX ? FRCT
???????STM ?????#coef_s,AR5
???????RPT ?????#3
???????MVPD ? #table_s,*AR5+
???????STM ?????#coef_s,AR3
???????STM ?????#d_xs,AR2
???????STM ?????#l_s,AR4
???????ST ??? #7FFFH,l_s
???????SQUR ? *AR2+,A
???????ST ??? A,*AR2
???????||LD ? *AR4,B
???????MASR ? *AR2+,*AR3+,B,A
???????MPYA ? A
???????STH ?????A,*AR2
???????MASR ? *AR2-,*AR3+,B,A
???????MPYA ? *AR2+
???????ST ??? B,*AR2
???????||LD ? *AR4,B
???????MASR ? *AR2-,*AR3+,B,A
???????MPYA ? *AR2+
???????ST ??? B,*AR2
???????||LD ? *AR4,B
???????MASR ? *AR2-,*AR3+,B,A
???????MPYA ? d_xs
???????STH ?????B,d_sinx
???????RET
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cosx:
??????? .def ?d_xc,d_cosx
??????? .data
table_c ?? .word 0249h ?????? ??;c1=1/(8*7)
??????? .word 0444h ??????????;c2=1/(6*5)
??????? .word 0aabh ??????????;c3=1/(4*3)
??????? .word 4000h ??????????;c4=1/(2*1) ??????
coef_c .usect ??"coef_c",4
d_xc ?? .usect ??"cos_vars",1
squr_xc ?? .usect ??"cos_vars",1
temp_c .usect ??"cos_vars",1
d_cosx .usect ??"cos_vars",1
l_c ??? .usect ??"cos_vars",1
???????.text
???????SSBX ? FRCT
???????STM ?????#coef_c,AR5
???????RPT ?????#3
???????MVPD ? #table_c,*AR5+
???????STM ?????#coef_c,ar3
???????STM ?????#d_xc,AR2
???????STM ?????#l_c,AR4
???????ST ??? #7FFFH,l_c
???????SQUR ? *AR2+,A
???????ST ??? A,*AR2
???????||LD ? *AR4,B
???????MASR ? *AR2+,*AR3+,B,A
???????MPYA ? A
???????STH ?????A,*AR2
???????MASR ? *AR2-,*AR3+,B,A
???????MPYA ? *AR2+
???????ST ??? B,*AR2
???????||LD ? *AR4,B
???????MASR ? *AR2-,*AR3+,B,A
???????SFTA ? A,-1,A
???????NEG ?????A
???????MPYA ? *AR2+
???????MAR ?????*AR2+
???????RETD
???????ADD ?????*AR4,16,B
???????
???????STH ?????B,*AR2
???????RET
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????????.sect ".vectors"
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????????.align ?0x80 ??????????; must be aligned on page boundary
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RESET: ?????????????????????????; reset vector
????????BD main ????????????????; branch to C entry point
????????STM #200,SP ????????????; stack size of 200
nmi: ???RETE ?????????????????; enable interrupts and return from one
???????NOP
???????NOP
???????NOP ?????????????????????????????;NMI~
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???; software interrupts
sint17 .space 4*16
sint18 .space 4*16
sint19 .space 4*16
sint20 .space 4*16
sint21 .space 4*16
sint22 .space 4*16
sint23 .space 4*16
sint24 .space 4*16
sint25 .space 4*16
sint26 .space 4*16
sint27 .space 4*16
sint28 .space 4*16
sint29 .space 4*16
sint30 .space 4*16
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int0: ??RETE
????????????????NOP
????????????????NOP
????????????????NOP
int1: ??RETE
????????????????NOP
????????????????NOP
????????????????NOP
int2: ??RETE
????????????????NOP
????????????????NOP
????????????????NOP
tint: ??B ? TINT_T0
????????????????NOP
????????????????NOP
????????????????NOP
rint0: ?RETE
????????????????NOP
????????????????NOP
????????????????NOP
xint0: ?RETE
????????????????NOP
????????????????NOP
????????????????NOP
rint1: ?RETE
????????????????NOP
????????????????NOP
????????????????NOP
xint1: ?RETE
????????????????NOP
????????????????NOP
????????????????NOP
int3: ??RETE
????????????????NOP
????????????????NOP
????????????????NOP
????????????????.end