hi everyone ...
yeah I'm trying to hook up a ADC0838 to my 8052. but the strange thing is that this chip is highly undocumented and I couldn't find any working examples.
I read the data sheet and I have everything done correctly but the ADC still gives me a stream of 0s when I connect 5 volts to the channel 1 input.

heres my code:
<code>
;Reads the ADC
;###########################################################################
ReadADC: mov R7,#5 ;set a counter for the 5 address bits
mov R6,#8 ;set a counter for the 8 input bits
clr CLK
clr ADCS ;start a conversion
ADILoop: rrc a ;move the bit into c
mov DIO,c ;move the bit into the IO line
call ADpulse ;send a clock pulse
djnz R7,ADILoop ;if the 6 bits have been transmitted then
mov a,#0
call ADpulse ;the initialization pulse
ADOLoop: call ADpulse ;Pulse, data is now available
mov c,DIO ;move the data in c
rlc a ;shift the bit in a
djnz R6,ADOLoop ;if the 8 bits have been recieved
setb ADCS ;disable the ADC
ret ;code in acc
;Creates a pulse for the ADC fuctionality
;###########################################################################
ADpulse: push b ;save b for now
mov b,#9
djnz b,$
setb CLK ;set the clock pulse
mov b,#9
djnz b,$
clr CLK ;clear the pulse
pop b
ret
</code>

yeah but I dont get any output. I have tried another chip in case this one is a goner but that didn't work either ... can someone help? I can send the circuit if it's needed.


Yeah thanks.
Nima