mardi 30 août 2011

let's Start .... again..

I tested the interface from Arduino to S&S using brand new 74HC126  .. result = not possible.
I tried to use them in a non-classical way  : output a "1" when input is Hight and High Z when input is low (using the internal pulldown resistor of Speech synth to get a low at -12V).After few tests it seems that connecting negative voltage to the HighZ output of the 74HC126 is not possible. (I get ~0.5v instead of -12V ). i don't know exactly why because i didn't check internal schematic of the 74HC126.
So .. bye bye  the 74HC126 ... and welcome back to the littles Transistors .. :)

For people asking for the code,I will release it, don't worry. Actually it doesn't work and i'm trying to identify the source cause of the prob. I will rebuild a new interface to ensure it doesn't interfere with S&S data bus

1 commentaire:

  1. Maybe your chip has an internal 5V zener protection for 5V TTL signals ?