>> and interrupt control. This allows the data path to the PC Card modem
>> to operate very much like a LAN adapter running in I/O mode.
ML> Anyone care to comment on the last bit about the PC Card modem running
ML> like a LAN adaptor?

The difference between this scheme and a real 8250 is that the card can
buffer the Rx data and trickle it out as fast as the host can service the
interrupts.

The problem with the 8250 is not primarily that it delivers one interrupt
per byte received, it's that ONCE a byte is received and an interrupt is
generated, any further bytes received are hurled into a black hole until
the host CPU can service the first interrupt and clear out the UART's Rx
buffer.

I have no idea why they didn't simply put 16550 emulation in, though.
Tweaking your Dreaded S-register O'Death will //significantly// reduce CPU
loading.

-- Lewin A.R.W. Edwards [Team OS/2]  Tel 0419320415 * 0412809805 * 0414927056
@EOT:

--- MsgedSQ/2 3.35