24 Nov
2015
24 Nov
'15
2:34 p.m.
From: Phil Budne
Any plans to allow USB "target" (as opposed
to "host" -- I dunno if
those are the correct terms)
'host' and 'device' are the two modes for USB, IIRC.
to allow the board to be connected to a modern
computer as a
peripheral?
Not sure I see the purpose? Any of the storage devices (SD card, or thumb
drive) can of course be pulled out and plugged into another machine.
From: Andrea
there's always the possibility to choose a
commercial development
board, and mount it as SOM over a larger board that would include only
psu and bus level translators. This way could be cheaper
That's basically what we're doing for the prototypes, except that our
prototype motherboard is wire-wrapped. The mobo (currently) has only i) bus
transceivers, ii) level converters from +5V logic to +3.3V (nobody supports
+5V in any modern FPGA part, and QBUS transceivers are pretty much only
available in +5V - although we'd be happy to be informed otherwise), and iii)
a pair of 64-pin DuPont connectors to a FPGA/uC board from ZTEX.
(We may add more, e.g. when we get to debugging the indicator panels, we'll
probably put the drivers on the prototype motherboard. Etc, etc. That's part
of the reason for going with wire-wrap, it's easy to add stuff like that.)
It is, alas, not that cheap overall. We think the production models, with all
the circuity on a single custom PCB, will be somewhat cheaper. In addition,
you can't really stack the ZTEX boards on another board, and meet the QBUS
inter-board spacing.
Noel