I/V转换波形输出电路
DAC0832为电流输出型转换器,一般要求输出是电压,所以还必须经过一个外接的运算放大器转换成电压。
如图3-23所示为一种用两级运算放大器组成的模拟电压输出电路。从第一个运放输出为单极性模拟电压,从第二个运放输出为双极性模拟电压。如果参考电压为+5V,则点a输出电压为0~-5V,点b输出电压为±5V。
图3-23I/V转换波形发生电路
波形发生
程序:
;******锯齿波图3-24******
ORG2000H
START:MOVDPTR,#7FFFH
MOVA,#00H
LP:MOVX@DPTR,A
INCA
SJMPLP
图3-24锯齿波形
;****三角波(图3-25)******
ORG2030H
START:MOVDPTR,#7FFFH
MOVA,#00H
UP:MOVX@DPTR,A
INCA
JNZUP
DECA
DOWN:DECA
MOVX@DPTR,A
JNZDOWN
INCA
SJMPUP
图3-25三角波形
;*****矩形波(图3-26)****
ORG2070H
START:MOVDPTR,#7FFFH
LP:MOVA,#DATAH
MOVX@DPTR,A
LCALLDELH
MOVA,#DATAL
MOVX@DPTR,A
LCALLDELL
SJMPLP
图3-26矩形波
;*****梯形波*****
ORG20A0H
START:MOVDPTR,#7FFFH
L1:MOVA,#DATAL-1
UP:INCA
MOVX@DPTR,A
CJNEA,#DATAH,L3
L3:JCUP
DOWN:LCALLDEL
L2:DECA
MOVX@DPTR,A
CJNEA,#DATAL,L4
L4:JCL1
SJMPL2
;*******正弦波图3-27*****
ORG000H
MAIN:MOVR1,#00H
LOOP1:
MOVA,R1
MOVDPTR,#SETTAB
MOVCA,@A+DPTR
MOVDPTR,#0BFFFH
MOVX@DPTR,A
INCR1
AJMPLOOP1
SETTAB:
DB80H,83H,86H,89H,8DH,90H,93H,96H
DB99H,9CH,9FH,0A2H,0A5H,0A8H,0ABH,0AEH
DB0B1H,0B4H,0B7H,0BAH,0BCH,0BFH,0C2H,0C5H
DB0C7H,0CAH,0CCH,0CFH,0D1H,0D4H,0D6H,0D8H
DB0DAH,0DDH,0DFH,0E1H,0E3H,0E5H,0E7H,0E9H
DB0EAH,0ECH,0EEH,0EFH,0F1H,0F2H,0F4H,0F5H
DB0F6H,0F7H,0F8H,0F9H,0FAH,0FBH,0FCH,0FDH
DB0FDH,0FEH,0FFH,0FFH,0FFH,0FFH,0FFH,0FFH
DB0FFH,0FFH,0FFH,0FFH,0FFH,0FFH,0FEH,0FDH
DB0FDH,0FCH,0FBH,0FAH,0F9H,0F8H,0F7H,0F6H
DB0F5H,0F4H,0F2H,0F1H,0EFH,0EEH,0ECH,0EAH
DB0E9H,0E7H,0E5H,0E3H,0E1H,0DEH,0DDH,0DAH
DB0D8H,0D6H,0D4H,0D1H,0CFH,0CCH,0CAH,0C7H
DB0C5H,0C2H,0BFH,0BCH,0BAH,0B7H,0B4H,0B1H
DB0AEH,0ABH,0A8H,0A5H,0A2H,9FH,9CH,99H
DB96H,93H,90H,8DH,89H,86H,83H,80H
DB80H,7CH,79H,78H,72H,6FH,6CH,69H
DB66H,63H,60H,5DH,5AH,57H,55H,51H
DB4EH,4CH,48H,45H,43H,40H,3DH,3AH
DB38H,35H,33H,30H,2EH,2BH,29H,27H
DB25H,22H,20H,1EH,1CH,1AH,18H,16H
DB15H,13H,11H,10H,0EH,0DH,0BH,0AH
DB09H,08H,07H,06H,05H,04H,03H,02H
DB02H,01H,00H,00H,00H,00H,00H,00H
DB00H,00H,00H,00H,00H,00H,01H,02H
DB02H,03H,04H,05H,06H,07H,08H,09H
DB0AH,0BH,0DH,0EH,10H,11H,13H,15H
DB16H,18H,1AH,1CH,1EH,20H,22H,25H
DB27H,29H,2BH,2EH,30H,33H,35H,38H
DB3AH,3DH,40H,43H,45H,48H,4CH,4EH
DB51H,55H,57H,5AH,5DH,60H,63H,66H
DB69H,6CH,6FH,72H,76H,79H,7CH,80H
END