0832的应用举例

Ex1：DAC0832与8086cpu的连接图如下所示。要求（1）写出端口地址；（2）写出产生矩形波、锯齿波和三角波的程序段。D7-D0WRY0G2AG2BCBA74LS138A2A1A0G1A7A3A8&A9A68086cpuDI7-DI0WR1WR2XFERCSIout1Iout2VccILE5VARfbRwVoutDGNDAGNDDAC0832VrefA5V15kΩ15kΩ7.5kΩR00.1uf...端口地址：278H矩形波程序段锯齿波程序段三角波程序段MOVDX,278HMOVDX,278HMOVDX,278HZ0:MOVCX,0FFHMOVAL,00HZ0:MOVCX,0FFHMOVAL,00HZ1:OUTDX,ALMOVAL,00HZ1:OUTDX,ALDECALZ1:OUTDX,ALLOOPZ1JMPZ1INCALMOVCX,0FFHLOOPZ1MOVAL,0FFHMOVCX,0FFHZ2:OUTDX,ALZ2:DECALLOOPZ2OUTDX,ALJMPZ0LOOPZ2JMPZ0Ex2：DAC0832、8255A与8086cpu的连接图如下所示。要求（1）写出端口地址；（2）写出产生三角波的程序段。D7-D0D7-D0RDRDWRWRA1A0A2A1Y2CSG2AG2BCBA74LS138A6A5A4G1≥1A0A9A8&A10A78086cpu8255ADI7-DI0PA7-PA0WR1WR2XFERCSIout1Iout2VccILE5VARfbRwVoutDAC0832Vref-5V端口地址：4A0H,4A2H,4A4H,4A6H程序段：MOVDX,4A6H；8255A初始化MOVAL,80HMOVDX,ALMOVAL,00HMOVDX,4A0HA1:OUTDX,AL；INCALCMPAL,0FFHJNZA1A2:OUTDX,ALDECALCMPAL,00HJNZA2JMPA1