9 Oct
2015
9 Oct
'15
7:44 p.m.
Quite a piece of work. I hope you can continue to plug away at it.
I get that bit about mistakes. Even my simple PIC-based Documation card
reader interface board had a mistake (fortunately, one I could easily
fix without having to create a new board). Fortunately, my Mark-8
boards ended up mistake free, but only because of hours and hours and
hours of cross-checking against the layouts in the Radio Electronics
sponsored flyer, the schematics and against know issues. But those were
nothing like this thing's complexity.
JRJ
On 10/9/2015 8:38 PM, John Wilson wrote:
This may never see the light of day (if the prototype
turns out to be
stillborn) but it's pretty and I can't resist posting a pic before I've
powered it on and proven its uselessness:
http://www.dbit.com/wilson/projects/qba.jpg
Officially it's for my morally repugnant attempts to earn a living (so it's
supposed to be a Q-bus bridge that connects over Ethernet), but I wanted to
still be able to do something fun in the very likely case that the Ethernet
port doesn't work (no idea if my PCB layout is kosher for something as fast
as the gigabit PHY's bus) or has uselessly high latency, so I added an SD
card slot and made all the CPU-end terminators switchable, so it can act
as just a plain peripheral (I'm mainly thinking disk controller -- I've
already found a reason why the USB device port can't work), if its CPU's
alive and can talk to the Q-bus. We'll see. Many many many chances for
mistakes. Five different power-supply voltages, for starters.
As always, I can't say enough good things about XMOS microcontrollers and
OSHpark.com.
John Wilson
D Bit
