[LispM-Hackers] Serial port progress
Sat Mar 30 16:12:00 2002
If you don't care about the bare iron port, you can skip this message.
(1) My funky cable works.
(2) I have managed to spit out characters first from Linux, and then
from my own e3 program, and see them in minicom on my development box.
(3) I am only doing output, not input (yet?).
(4) Since I'm only doing output, I haven't screwed around with
enabling interrupts for the UART.
(a) The PC is an ugly, ugly piece of work. If I had a dog that looked
like that, I'd shave it's ... and make it walk backwards.
(b) I used the BIOS to set baud rate and other things before I jump to
(c) The CPU can pump data at the UART way faster than it can handle
it. I have not explored checking the various registers (I/O ports) to
see when it's ready for another char. I assume that I can deduce this
from the I/O ports. I will probably just busy wait. This will
resurrect the old UNIX "nothing runs while the kernel printfs"
On another note, I needed to do this because I was having trouble with
the SVGA stuff -- in particular, writing past the end of the first
memory bank. This should make it easier to debug.
==== John Morrison
==== MAK Technologies Inc.
==== 185 Alewife Brook Parkway, Cambridge, MA 02138
==== vox:617-876-8085 x115