Interfacing TTL and CMOS logic

[Joachim Verghese]

Hi,

> If a pin is configured as an input, it will float at high impedance - this
> can then be pulled up to 15v with a resistor.

Just make sure your microcontroller pins can withstand such
voltages.

> Ok, if you want to do several lines some sort of open collector buffer
> chip would be the way to go in terms of PCB real estate.

I guess the classic approach would be to use 7406 or 7407 buffers,
but personally I would go for transistor arrays such as ULN2003
or ULN2803.

cheers,

-joachim