Re: Can I use DOSEMU for testing device driver code?

[Edenyard <mail@edenyard.co.uk>]

easlab@absamail.co.za wrote:

> All my DOS application can't do is toggle 2 pins of the par-port.
> No interupts.      dosemu-1.1.99 as root, won't do it, even with
> editing dosemu.conf to:
>      $_ports { device /dev/lp1 fast range 0x378 0x37f } # lpt1
> and other combinations
> 
> Under DOS these are the correct port addresses.
> Has any body ever done this ?
> 
> == Chris Glur.

	It appears that DOSEMU has BIG problems when one wants to do this sort
of thing and nobody quite seems to know why. Some time ago, I posted a
similar problem about a DOS program that I had which writes characters
to a serial port and then has to toggle the RTS line (within 50
milliseconds of the last bit of the last character going out of the TX
shifter) so that the reply can come back - the RS232 interfaces to a
half-duplex RS485, hence the RTS controls direction, send or receive.

	I find that I can write the characters in my program when running under
DOSEMU 1.1.99 and they do eventually come out of the socket round the
back of the PC but there's no telling when. That makes it impossible to
know when to toggle RTS, since reading the correct status bit
(presumably emulated by DOSEMU, not the REAL bit in the UART) to see when
the shifter's empty is obviously NOT related to the timing of the actual
characters coming out of the hardware.

	I, like you, have tried all sorts of permutations of using $_ports,
etc., but to no avail. If you ever find a solution, I'd be delighted to
hear it. Last time I asked about this on the mailing list, the response
I got was, "What's RTS?".... That wasn't from Bart, by the way. He seems
to have answers for most things. Not for this, though!

	Cheers,

		Gerald.