greg

So, basically you are suggesting using a shift register to serially drive opto-couplers? Makes sense. Complicates the setup, but will investigate. Thanks! Still would love to know if there is a technical limit on the combined chip-wide digital...

Hi, We need to drive a dozen or so opto-isolated solid state relays (i.e. PC817) to trigger external devices that basically just expect a "short" to turn on. Using T4, and a series resistor, so the load on each pin ends up being around 6ma (I...