[J-core] Checking in.

wjones at wdj-consulting.com wjones at wdj-consulting.com
Fri Dec 6 12:48:07 UTC 2019

While this is on my mind...

How many UARTs are available on TurtleBoard? I don't actually plan to use 
the Ethernet on my TurtleBoard. Instead, I plan use PPP to connect it to the 
Internet (it'll connect a UART to a wifi-enabled board's secondary UART). If 
there is only room for one UART plus Ethernet, is it possible to accommodate 
my requirement and replace Ethernet with a second UART in the bitstream?

The (Net)BSD getty is smart enough to multiplex pppd and login when only a 
single UART is available, but I don't believe any Linux getty 
implementations have this feature...

-----Original Message----- 
From: Rob Landley
Sent: Thursday, December 05, 2019 11:55 PM
To: j-core at lists.j-core.org
Subject: [J-core] Checking in.

Turtle boards have arrived in Canada and Jeff is taking a few to Japan with 
I believe he's attending Tron Show and should have at least one with him. We
still plan to get them up on crowdsupply early in the new year, but haven't
finished all the bitstream bits to support framebuffer and audio and such 

(We also switched from lx25 to lx45 this batch, and the ethernet in the
bitstream doesn't work because we haven't redone the constraints file yet.
Different pinout, the circuitry is being constrained to the wrong part of 
FPGA so the traces are too long and the timing's wrong. All the other I/O 
at least at the smoketest level.)

We have a longish todo list for our next engineering sprint, but haven't 
to coordinate schedules quite yet. We think we've come up with two small
extensions to the j-core instruction set that would let us do the fast 
transforms needed for realtime GPS acquisition (yay). I should do a writeup 
that, but we want to actually implement it first.

I need to completely redo the website but haven't quite opened that can of 
yet. Still collecting material, such as the start of a writeup on place and
route at:


Activity continues behind the scenes. Juggling a lot of balls...

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William D. Jones
wjones at wdj-consulting.com 

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