RTEMS...kbd handler

[Joel Sherrill <joel@merlin.gcs.redstone.army.mil>]

On Sat, 22 Mar 1997, Kurt Van Delden wrote:

> I know this is not the primary topic of the mailing list, but here it goes.

Since there is currently no dedicated rtems list, this is as good a place 
as any. :)

> I have rtems 3.60 & newlib 1.70 setup as follows:
> 	target: i386-go32-rtems
> 	host:   i586-unknown-linux
> It works....
> 	I can compile the examples.  In addition I have constructed a serial
> driver from various sources.  My current difficulty is detecting if a key
> stroke is available.. I don't know if newlib has a "kbhit" equivalent.  I
> can link libpc.a in, yet this doesn't seem to help,.  kbhit nor
> bioskey(0x01) do the trick.  If I use scanf, rtems doesn't deschedule the
> process voluntarily.  Scanf seems to poll for keys, and only gets
> descheduled when the time-slice is up.  Does RTEMS have it's own kb
> handler, or does it use djgpp's/dos' ?

The place to look is in c/src/lib/libbsp/i386/go32/console.  In the 
console driver, you will see that read boils down to a call to inbyte()
which in turn calls a routine _IBMPC_inch().  This polls for a character 
to become available using the _IBMPC_chrdy() call.  The driver appears to 
provide it's own ISR handler but has no mechanism to block in terms of OS 
services until a keystroke is available.  It polls for the availability 
of a character in the ISR buffer or until "kbhit()" retuns 1.

We would like to merge your serial driver into the source and if you are 
so inclined to provide blocking keyboard input, let me know.  I may be 
able to cut down on the work required to do this.

--joel
Joel Sherrill                    Sr. Computer Scientist
joel@OARcorp.com                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
   Support Available             (205) 722-9985