要測試這個線路的ASSEMBLE 應怎樣寫?? #program 上改動 那12BIT的數值 ***** P1...接dac的12bit p3.2是CS P3.0是 A0,A1 P3.1是A2,A3 ogh 00h LJMP MAIN MAIN: MOV a,#0ffh <----測試的數值 MOV P1, A SETB P3.2 SETB P3.0 CPL P3.1 END 就這樣可以嗎?? 但是我試了還是不能..有人能幫到我嗎??? 發表人 - cyw1984 於 2005/09/12 21:36:03

0- 10v Vin - 12v可以嗎??

您這接法將A0,A1接一起;A2,A3接一起,只能做  All latches transparent & NOP  (DB11:DB8 & DB3: DB0 共同,故都將只寫入同一內容), 且您的程式 /CS pin (P3.2) 在 SETB P3.2後一直為 "H" 無法 enable Ad667 工作! 另您應查一下 8051 的 /WR 是否以 MOVX 才會動作呢? sorry! 51好久沒玩了,一時無法確認!如有誤請更正. Thanks!!

1. If I use only one AD667 May I use the 8051 port to control trigger the CS without Address decoder?? Port 3.2,Is it OK?? Thanks I fixed my program............ (p3.2 is CS P3.0 is A0,A1 P3.1 is A2,A3 ) <---IS IT OK???HAVE PROBLEM?? ogh 00h LJMP MAIN MAIN: MOV a,#111111111111B ;test values MOV P1, A CRL P3.2 ; trigger the AD667 NOP NOP SETB P3.1 CPL P3.0 ; enable 8 LSB to first latch CPL P3.1 SETB P3.0; enable 4 MSB to first latch and load the first latch to second latch NOP NOP SETB P3.2 ; No operation of AD667 END Is it correct??

Hi CYW1984: First, you should decide which method to control the AD667. ****************** A. 4 bits bus ****************** 1./CS go low to active AD667 2.Set [A3:A0] to 1110B to active 4LSB of 1st rank 3.Set [D3:D0] data to DB bus of AD667 4.Crate a negative pulse for /WR let AD667 latch data to 1st rank. 5.Set [A3:A0] to 1101B to active 4 Middle bits of 1st rank 6.Set [D7:D3] data to DB bus of AD667 7.Crate a negative pulse for /WR let AD667 latch data to 1st rank. 8.Set [A3:A0] to 1011B to active 4 MSB bits of 1st rank 9.Set [D11:D8] data to DB bus of AD667 10.Crate a negative pulse for /WR let AD667 latch data to 1st rank. 11.Set [A3:A0] to 0111B to active load data form 1st rank to 2nd rank 12.Crate a negative pulse for /WR let AD667 latch data to 2nd rank. 13. Set /CS go high 14. Set NOP code to avoid un-know situation. ****************** B. 12 bits bus ****************** 1./CS go low to active AD667 2.Set [A3:A0] to 0000B to latch transparent 3.Set [D11:D0] data to DB bus of AD667 4.Crate a negative pulse for /WR let AD667 latch data to 1st rank. 5. Set /CS go high 6. Set NOP code to avoid un-know situation. So AD667 only support 2 method to operation, 1st be configuration on 4 bits system and 2nd method can operation on 12 or 16 bits system. you can configuration your 8051 mapping the 12bits bus (P2[3:0] P1[7:0]) with other control signal (may P2[7:4] map to A[3:0], P3 control /CS,/WR).. Finally, I make sure the /WR signal of 8051 only active when MOVX be excuting.(external IO write); If you insit to use MOV insruction, should use another pin to control /WR of AD667.

Sorry! you have another question for the input rigion; The spec. of AD667 can operate between -10 and +10 V when device supply +/- 12.5V. May you addition an attenuator (x3 ) to reduce input swing to +/-4V then you can select +/-5V mode to get the best resolution!! +/-12V can input to AD667 without damege but over +/-10V region may no effect on the digital output code. (exp 10V -> 0x0fff & 10.1 to 12V still output 0x0fff)     Data-sheet http://www.analog.com/UploadedFiles/Data_Sheets/88155358AD667_a.pdf

Hi: cyw1984  I attached a chart for 12-bits programming method, maybe you have some ideals from this chart. Regards!

引言: Hi: cyw1984 I attached a chart for 12-bits programming method, maybe you have some ideals from this chart. Regards!

THANK YOU .......... 12BIT已完成了~~現在試16BIT中 發表人 - cyw1984 於 2005/09/17 00:40:32