单片机实验之DA转换实验.doc

一、实验目得
1、掌握单片机与DAC0832得接口设计方法。
2、掌握Proteus软件与Keil软件得使用方法。
二、设计要求
1、用Proteus软件画出电路原理图,在单片机得外部扩展片外三总线,并通过片外三总线与0832接口。
2、在单片机得外部扩展一个4个按键得键盘。
3、按下K0,产生连续方波信号。
4、按下K1,产生连续锯齿波信号。
5、按下K2,产生连续三角波信号。
6、按下K3,产生连续正弦波信号。
7、通过外接示波器观察波形。
三、 电路原理图

六、 实验总结
通过本次实验电路得设计掌握了基本得DA转换电路单缓冲得设计;参考电压得选择;0832得片选;集成运放芯片得选择及接线;尤其就是运放得反馈电阻,从而能够产生正常得波形。
七、思考题
1、编程实现产生连续梯形波信号。
答:程序见程序清单。
四、 实验程序流程框图与程序清单
ORG 0000H
/***********起始程序***********/
START: LJMP MAIN
ORG 0100H
/***********监控程序***********/
MAIN: MOV SP, #60H
LOOP: LCALL KEYSS
LJMP LOOP
KEYSS: LCALL KEY
JB 20H、0 ,KEYAA
JB 20H、1 ,KEYBB
JB 20H、2 ,KEYCC
JB 20H、3 ,KEYDD
JB 20H、4 ,KEYEE
RET
/***********键功能程序*/
KEYAA: MOV R2 ,#00H ;锯齿波
LOOP1: MOV DPTR ,#0000H
MOV A ,R2
MOVX DPTR ,A
DEC R2
LCALL KEYSS
LJMP LOOP1
KEYBB: MOV DPTR ,#0000H ;矩形波
LOOP2: MOV R3 ,#0FFH
MOV A ,R3
MOVX DPTR ,A
LCALL DELAY
LCALL KEYSS
MOV R3 ,#00H
MOV A ,R3
MOVX DPTR ,A
LCALL DELAY
LCALL KEYSS
LJMP LOOP2
KEYCC: MOV R2 ,#00H ;三角波

MOV DPTR ,#0000H
LOOP3: MOV A ,R2
MOVX DPTR ,A
INC R2
LCALL KEYSS
CJNE R2 ,#0FFH ,LOOP3
LOOP4: MOV A ,R2
MOVX DPTR ,A
DEC R2
LCALL KEYSS
CJNE R2 ,#00H ,LOOP4
LJMP LOOP3
KEYDD: MOV R2 ,#00H ;正弦波
LOOP5: MOV DPTR ,#SIN
MOV A ,R2
MOVC A ,A+DPTR
MOV DPTR ,#0000H
MOVX DPTR ,A
INC R2
LCALL KEYSS
LJMP LOOP5
KEYEE: MOV R2 ,#00H ;梯形波
MOV DPTR ,#0000H
LOOP6: MOV A ,R2
MOVX DPTR ,A
INC R2
LCALL KEYSS
CJNE R2 ,#0FFH ,LOOP6
LCALL DELAY20ms
LOOP7: MOV A ,R2
MOVX DPTR ,A
DEC R2
LCALL KEYSS
CJNE R2 ,#00H ,LOOP7
LCALL DELAY20ms
LJMP LOOP6
/*******常数表格***********/
SIN:
DB 07FH ,082H ,085H ,088H ,08BH ,08FH ,092H ,095H ,098H ,09BH ,09EH ,0A1H ,0A4H ,0A7H ,0AAH ,0ADH
DB 0B0H ,0B3H ,0B6H ,0B8H ,0BBH ,0BEH ,0C1H ,0C3H ,0C6H ,0C8H ,0CBH ,0CDH ,0D0H ,0D2H ,0D5H ,0D7H
DB 0D9H ,0DBH ,0DDH ,0E0H ,0E2H ,0E4H ,0E5H ,0E7H ,0E9H ,0EBH ,0ECH ,0EEH ,0EFH ,0F1H ,0F2H ,0F4H
DB 0F5H ,0F6H ,0F7H ,0F8H ,0F9H ,0FAH ,0FBH ,0FBH ,0FCH ,0FDH ,0FDH ,0FEH ,0FEH ,0FEH ,0FEH ,0FEH
DB 0FEH ,0FEH ,0FEH ,0FEH ,0FEH ,0FEH ,0FDH ,0FDH ,0FCH ,0FBH ,0FBH ,0FAH ,0F9H ,0F8H ,0F7H ,0F6H
DB 0F5H ,0F4H ,0F2H ,0F1H ,0EFH ,0EEH ,0ECH ,0EBH ,0E9H ,0E7H ,0E5H ,0E4H ,0E2H ,0E0H ,0DDH ,0DBH
DB 0D9H ,0D7H ,0D5H ,0D2H ,0D0H ,0CDH ,0CBH ,0C8H ,0C6H ,0C3H ,0C1H ,0BEH ,0BBH ,0B8H ,0B6H ,0B3H
DB 0B0H ,0ADH ,0AAH ,0A7H ,0A4H ,0A1H ,09EH ,09BH ,098H ,095H ,092H ,08FH ,08BH ,088H ,085H ,082H
DB 07FH ,07CH ,079H ,076H ,073H ,06FH ,06CH ,069H ,066H ,063H ,060H ,05DH ,05AH ,057H ,054H ,051H
DB 04EH ,04BH ,048H ,046H ,043H ,040H ,03DH ,03BH ,038H ,036H ,033H ,031H ,02EH ,02CH ,029H ,027H
DB 025H ,023H ,021H ,01EH ,01CH ,01AH ,019H ,017H ,015H ,013H ,012H ,010H ,00FH ,00DH ,00CH ,00AH
DB 009H ,008H ,007H ,006H ,005H ,004H ,003H ,003H ,002H ,001H ,001H ,000H ,000H ,000H ,000H ,000H
DB 000H ,000H ,000H ,000H ,000H ,000H ,001H ,001H ,002H ,003H ,003H ,004H ,005H ,006H ,007H ,008H
DB 009H ,00AH ,00CH ,00DH ,00FH ,010H ,012H ,013H ,015H ,017H ,019H ,01AH ,01CH ,01EH ,021H ,023H
DB 025H ,027H ,029H ,02CH ,02EH ,031H ,033H ,036H ,038H ,03BH ,03DH ,040H ,043H ,046H ,048H ,04BH
DB 04EH ,051H ,054H ,057H ,05AH ,05DH ,060H ,063H ,066H ,069H ,06CH ,06FH ,073H ,076H ,079H ,07CH
/***********键扫子程序*********/
KEY: LCALL KEYCHULI
JZ EXIT
LCALL DELAY
LCALL KEYCHULI
JZ EXIT
MOV B ,20H
KEYSF: LCALL KEYCHULI
JZ KEY1
LJMP KEYSF
KEY1: MOV 20H ,B
EXIT: RET
KEYCHULI:PUSH PSW
CLR RS1
SETB RS0
MOV P1 ,#0FFH
MOV A ,P1
CPL A
MOV 20H ,A
CLR RS1
CLR RS0
POP PSW
RET
/*******延时子程序**********/
DELAY: MOV R7 ,#01H ;延时1ms
DL1: MOV R6 ,#8EH
DL0: MOV R5 ,#02H
DJNZ R5 ,$
DJNZ R6 ,DL0
DJNZ R7 ,DL1
RET
DELAY20ms: MOV R6,#0D7H ;20ms
DL2: MOV R5,#2DH
DJNZ R5,$
DJNZ R6,DL2
NOP
NOP
RET
END

五、 实验结果(波形图)