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.