Al Williams wrote:

> For Windows 95 and NT, the serial port is pretty easy.
> Open the COM Port using CreateFile().
> Then you can use GetCommModemStatus() to read CTS/DSR (but not RX).
> You can set the outputs (RTS/DTR/TX) using EscapeCommFunction().

Thanks for the tip.

Are there any similar techniques for bit-twiddling LPT signals?
I thought of using an LPT to load I/O bits into 4094 shift regs,
in order to program PROMs and the like.

This leads to another question: how would one generate reasonably
accurate programming pulse times? EPROMs need pulse resolution
around a millisecond. From DOS, I could read the timer hardware,
but on Win95 I'd expect a message about an I/O access without
permission. As everything gets more virtual, such access becomes
less feasible. And I can't see OS writers providing facilities
for such fine-scale timing.

I have seen EPROM programmer designs where they have an on-board
monostable. This makes the design portable across hardware and
software, because it's independent.