On Wed, Oct 7, 2020 at 11:04 AM Paul Koning <paulkon...@comcast.net> wrote: > > > On Oct 7, 2020, at 12:06 PM, Glen Slick via cctalk <cctalk@classiccmp.org> > > wrote: > > > > ... > > I was curious about this DEC M8704 DMS11-DA that sold cheap a few days > > ago. It has eight SMC COM5025 "Multi-Protocol Universal Synchronous > > Receiver/Transmitter USYNR/T" chips: > > > > https://www.ebay.com/itm/373243388363 > > > > Apparently it can't do anything on its own. It needs to be connected > > to a UNIBUS through a companion KMC11 processor board, which might not > > be too common if someone wanted to put together a working > > configuration. > > That model number isn't familiar. > > A KMC-11 is simply a microprocessor that sits on the Unibus and does Unibus > cycles to another device on behalf of the host. The idea is to offload > operations so the host can ask for block transfers and the KMC does the > individual character I/O operations needed. > > That said, it clearly is not correct that "it can't do anything on its own". > The KMC-11 reaches into the device via its Unibus CSRs. If you can find a > description of its operation, or reverse engineer it, you can clearly write a > device driver for it that doesn't rely on a KMC-11. > > paul
Well it does appear that M8704 DMS11-DA "can't do anything on its own" directly through the UNIBUS. From a quick visual inspection it only has power and grant continuity traces on the card edge connectors. The connection to the controlling KMC-11 is through the 40-pin Berg connector. So without a KMC-11 an alternate interface through the 40-pin Berg connector would be needed.
