[SunHELP] URGENT: TTL pulse on serial or parallel port

[James Lockwood]

On Thu, 19 Apr 2001, Wolfgang Engelien wrote:

> I would like to give out a ttl pulse
> (length anything between 50-300 ms,
> signal change from constant 0-5V to
> any other value within 0-5V) on either
> a serial port or the parallel port on
> an Ultra2.
>
> Does anybody have a hint on how to do this
> or where to get information about this.

One way (if you only need one bit) is to open a serial port and use
ioctl() to toggle RTS.

If your port is set up for EIA232 then the voltage levels will flip
+12/-12 but this is easy to adapt to your requirements in hardware.

-James