ADC0809CCN (almost = to ADC0808CCN)       
(8 bit, 8 channel A/D converter)

                    +---------------+
              IN3   |  1         28 |  IN2
              IN4   |  2         27 |  IN1
              IN5   |  3         26 |  IN0
              IN6   |  4         25 |  A0
              IN7   |  5         24 |  A1
    Start Convert   |  6         23 |  A2
   End of Convert   |  7         22 |  Addr Latch Enable
               D3   |  8         21 |  D7
    Output Enable   |  9         20 |  D6
            Clock   | 10         19 |  D5
              Vcc   | 11         18 |  D4
          Vref(+)   | 12         17 |  D0
              Gnd   | 13         16 |  Vref(-)
               D1   | 14         15 |  D2
                    +---------------+

 





For the logic, handle it just like a typical peripheral chip or static RAM.
(RD -> OE, some address valid signal -> ALE, 8 bit data bus, etc.) (The End of 
Convert signal could be polled or used as an interupt) For the analog, maximum 
input voltage <= Vcc (6.5 V absolute max).

The easiest way to use the part is to use Vcc = 5.12 volts, then connect 
Vref(+) to Vcc and Vref(-) to Gnd.  Gives you 5.12 / 256 = .02 volts/ bit.

Min start pulse and ALE pulse = 200 usec (max)
address setup time = 50 usec (max)
address hold time = 50 usec (max)
Output enable to data out = 250 usec (max)
Clock frequency = 10 (min) - 640 (nom) - 1280 (max) KHZ                       

Conversion time @ 640 KHZ = 100 usec

Operation is:

1)  latch the address of the analog input you want.
2)  signal start of conversion ( high going pulse >= 200 usec )
3)  wait until End of conversion returns to a high state
4)  read the data from the part.
5)  repeat as needed.

  


 

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