使用DAC接口生成三角波
我们编写了一个8085汇编语言程序，用于使用数模转换器(DAC)接口生成三角波。在CRO上可以看到波形的显示。
让我们考虑这个领域的问题解决方案。问题指出：为了获得单极性输出，J1在接口上短接到J2。要在CRO上显示波形，请将连接器P1的引脚1连接到CRO信号引脚，并将连接器P1的引脚2连接到CRO接地引脚。
程序
; FILE NAME DAC_TO_TRIANG.ASM ORG C100H X DW 00FFH ; the fall of rise and time I proportional directly to the value. ORG C000H PA EQU D8H PB EQU D9H PC EQU DAH CTRL EQU DBH MVI A, 88H OUT CTRL ; Purpose to configure 8255 ports ; The next 7 instructions will generate rising portion of the triangular waveform. ; And it is done by sending to DAC through Port A values from 00H to FFH, ; in steps of 01. Also the increment will be done after a small time delay here. LOOP: MVI A, 00H ASCEND: OUT PA PUSH PSW CALL DELAY POP PSW INR A JNZ ASCEND DCR A ; Now A contents will be FFH DESCEND: OUT PA PUSH PSW CALL DELAY POP PSW DCR A CPI FFH JNZ DESCEND JMP LOOP ; These Subroutines are used only for the generation of delay ; which is proportional to all the contents of word located at X. DELAY: LHLD X AGAIN: DCX H MOV A, H ORA L JNZ AGAIN RET