Jeremy Cooper <jeremy@broder.com> writes:

> On Mon, 19 May 1997, Erik E. Fair wrote:
> 
> > Does anyone know what chip(s) are used to make that parallel port? I mean,
> > how hard could it be to move bytes in & out of a parallel port?
> 
> With a little research, I found that the parallel port chip that Sun uses
> is 100% compatible with the IBM/XT/AT chip.  I created a parallel port
> driver for the sun 3/80 from the source for the IBM PC lpt driver, but I
> haven't commited it because it causes an unending chain of interrupts when
> it is finished with its I/O.  (not hard to fix)

I don't know about the Sun3, but the Sun4m bpp ports use the same DMA
engine as the esp and ledma, so the driver actually has to be somewhat
similar to the disk/ethernet drivers...it doesn't look too hard to
write one from the NCR chip docs, but I haven't had motivation or time
to do it...

--Aaron