Raghunathan r wrote:
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Today being Sunday I am a bit relaxed and not at my very best. Still I tried to read and understand that above paragraph at three different times of the day . Still trying.

Raghu

:) its ok i have managed this problem and now i got digital signals as output from ADC by connecting "OEC, SC & ALE" togather using mode "0".

so now i have to move with the subject to get control of three channals " address bits".

do you have any idea how to get control of that without MCU.

incase of, there is no way to get control withou MCU, so i have three ports of 8255 connecting to "P0" of AT89C52. but i have no idea how to talk to that registers.

i have seen the datasheet of the C52 EVB, they mentioned the port addresses are as follow;

PORTA = 0x0000,
PORTB = 0x0001,
PORTC = 0x0002 and
Control Register = 0x0003.

e.g. to write control register for all output mode

MOV A,#80H
MOV DPTR,#0003
MOVX @DPTR,A

the control word is 0x80.

but i dont understand it. so have you any idea how to make it as I/O to get control over ADC addresses and signal control.

"PORTA = 0x0000" as input and
"PORTB = 0x0001" as output.

i wanna to sign these control signals with one port as O/P and one as I/P

AD_OE ; Output enable
AD_SC ; Start conversion
AD_EOC ; End of conversion
AD_ALE ; address lacth enable
AD_CLK ; clock

AD0 ; mutiplexer channel addressing
AD1
AD2

i will be thankful to you if you can show me how to sing this address with "PORTA" as I/P, and with PORTB as O/P

Regards
Albarkani