Re: BLT32 on VMEBus

[email protected] wrote:

> I'm now wondering how to use BLT32 (block transfer) or even interrupts.
> Is there any documentation, or has anybody ever done this?

The MVME147 is not capable of performing VMEbus BLTs (at least not as a
bus-master).

Assuming you're still using mmap(2) to access the VMEbus from a userland
application, it is not possible to hook interrupts.

> Access on a D32 basis is quite slow and my ADC board attached to the
> VMEBus allows BLT mode.

Even with a board which does support BLTs, it would almost certainly
require the use of a DMA engine in the host/VMEbus bridge. At the present
time, there is no framework in NetBSD's VMEbus architecture to support
bus-master DMA engines on the bridge. Even if there was, it would only be
of use to an in-kernel driver.

Also bear in mind the MVME147 isn't the fastest of machines. You'll have
to resort to hand-optimised assembler to get the most out of it.

Cheers, Steve