OT: A call to arms (sort of)

From: Dwight Elvey <elvey_at_hal.com>
Date: Tue Jul 6 14:10:51 1999

"Richard Erlacher" <edick_at_idcomm.com> wrote:
> I>There's no reason not to use this type of DMA on a homebrew system.
> >There's no reason not to use cards that have the same form factor and
> >same connectors and ISA cards.
> >
> I've seen little reason to use DMA at all when processors generally have the
> capacity to move data at the bus bandwidth with block transfer instructions.
> It's not a religious issue for me to call the bus whatever seems
> appropriate. ISA is the "standard" developed around the PC. The signals
> are, for the most part, the obvious ones for ANY microprocessor. The
> interrupts are the exception, in that they use the ancient and stupid intel
> method, namely positive-going and, as you said, edge sensitive interrupts,
> which preclude the more sensible approaches to interrupt management.

 I thought I'd mention, the edge sensitive was a IBM issue,
not specifically Intel.
 On a side issue. I have connected two ISA cards to a vary
non-Intel processor ( NC4000 ). I have a older MFM HD controller
and a floppy controller connected. The HD, of course, doesn't
need DMA but the FDC normally ran with DMA. Since I had no
interrupt on my setup, I was able to dedicate the processor
to reading the FDC. The only problem I had was that the processor
was a little to fast for the controller chip and the status
from the internal state machine required me to put a delay
loop in the code. This processor had no block move instructions
but ran fast enough that it wasn't an issue.
Received on Tue Jul 06 1999 - 14:10:51 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:32:11 BST