10 Dec
2003
10 Dec
'03
10:44 a.m.
On Wednesday 10 December 2003 10:47, Peter C. Wallace wrote:
Let's add the PERQ 2T2, the OMTI5200 series controllers (used in PERQ
3a's, Torch XXX's, etc), the Adaptec ACB4000, the Xebec whatever, the
Xeroc Daybreak, another Q-bus PDP11 controller, which pretends to be an
RP-something on the PDP11 side (it doesn't use MSCP), and a couple of
others.
Usually you know the encoding scheme, and I dont
see anything wrong
with using whatever knowledge you have of the interface to optimize
it. If a different encoding scheme is used, an FPGA based design
could easily adapt.
"Knowing the encoding scheme" prevents this from being a "universal"
interface. You'd need to make different version for, say, your PC/XT,
your PDP-11 with an RQDXn, and TeleVideo TS816. (Or shouse I say "my" as those are all system I have that'd benefit from
this). At most, (I
think) you'd need a different cable set for all three of these if you
didn't claim to "know" the encoding.
Don't all ST506 drives have a 34 pin control connector and a 20 pin data
connector? There were a couple of changess to the former (most common
being that pin 2 (IIRC) changed from RWC/ to HS3/) but apart from that,
the pinout was standardised.
Also, with at least two of these examples, you
probably *don't* know the
encoding method... as mentioned earlier, the RQDX(1) isn't based on any
'standard' controller IC. Also, the TeleVideo's controller is based
upon an 8X300 microprocessor, and may not be RLL/MFM/FM.
At least you _could_ trace out the schematics (if you don't already have
them) and disassemble the 8X300 code. No I am not suggesting you need to
do this, but it's a lot easier than figuring out what happens inside an
ASIC..
-tony