Dec 8235 IC?

On 03/09/2015 09:05, simon wrote: Ow. I don't have a list, but I do have a copy of the 1976 Signetics ICs databook, which lists a lot of 82xx logic. I've not checked one of my M8330 boards but I guess that's what you need. 8235 is a quad (4-bit) 2-input multiplexer - with a twist. It has open collector outputs and two control inputs. The twist is that one of each pair of inputs is non-inverting, the other is inverting, and the idea is that by tying the two inputs together you can use the control inputs to make the outputs the TRUE or COMPLEMENT of the input data, eg to feed to an adder. The data sheet is two pages, which I can scan if you want. The An and Bn data inputs are pins 1 and 2, 6 and 5, 10 and 11, 15 and 14; corresponding f0 to f3 outputs are pins 3, 4, 12 and 13. S0 and S1 are pins 9 and 7. Vcc is pin 16, GND is 8. Truth table: S0 S1 fn ---- ---- ---- 0 0 /An.Bn 0 1 Bn 1 0 /An 1 1 1 I like the last paragraph of the description. "The 8234 and 8235 designs have open collector outputs which permit direct wiring to other open collector outputs (collector logic) to yield 'free' four-bit words. As any as one hundred four bit words can be multiplexed by using up to fifty 8234/8235 in WIRED-AND mode." Good thing DEC didn't go quite that far. -- Pete Pete Turnbull