The VCCPLL line is extraordinarily sensitive to voltage rise times, and
appears to cause the FPGA to go into latchup very very easily.
As a result, the VCCPLL regulator burns all 250 mA of its budget
constantly, as the FPGA shunts VCCPLL to GND. This would be ideal
during an ESD event, but not ideal during normal operations.
Indicate the VCCPLL Regulator approach is DNP, and that the VCCPLL
Filter Network is preferred. Mostly because the regulator doesn't work
at all.
Signed-off-by: Sean Cross <sean@xobs.io>
This is another example of a 3D model that has gotten moved, causing
kicad to not work between versions. Use a local copy of the 3D model.
Signed-off-by: Sean Cross <sean@xobs.io>
It turns out that if you put pads down on the silk layer, kicad doesn't
export them. As a result, evt1 had no pin1 marker for this LED.
Signed-off-by: Sean Cross <sean@xobs.io>
Previously, we used text to display the "5" and "6" designators for the
physical buttons. Replace this with a value of "5" and "6", and remove
the extra text.
Additionally, display "SW??" under the switch, to make hand-assembly
easier.
Do the same thing for the "Reset" button.
Signed-off-by: Sean Cross <sean@xobs.io>
Change the "Value" of the user switch from "USER1" and "USER2" to "5"
and "6". This way we can use the "Value" as the silk rather than adding
another text layer.
Signed-off-by: Sean Cross <sean@xobs.io>
Some components were getting added to the BOM that shouldn't have been,
and some were missing from the pick-and-place file.
Update the `Placement Type` to be accurate according to assembly.
Signed-off-by: Sean Cross <sean@xobs.io>
Move some vias around to get the 5V plane more breathing room. Add a
small pour to give more copper and stabilize the net.
Signed-off-by: Sean Cross <sean@xobs.io>
Add more 5V vias near the 1.2V regulator, and replace a manual trace
with a copper pour. This will increase the amount of copper going to
both the 3.3V and 1.2V regulators, which should improve stability.
While we're at it, remove an errant silk artifact on the USB connector.
Signed-off-by: Sean Cross <sean@xobs.io>
Add a note indicating the PCB thickness and color.
Also, move the drill origin to the lower-left corner, to aid in machine
assembly.
Signed-off-by: Sean Cross <sean@xobs.io>
Add more silk, indicating website and other info.
While we're at it, move some traces around to give more copper area, and
drop some more vias to improve ground performance.
Signed-off-by: Sean Cross <sean@xobs.io>
The Kicad default footprints seem volatile and unreliable. Going
between two machines that both have "Kicad 5.0.0" installed results in
incompatibilities because KiCad has renamed their footprint libraries.
Also, for some reason it's going to Github to get footprints instead of
using local copies.
Copy every model and footprint we use into a local tomu-fpga.pretty.
This lets us ensure we can work offline, and also allows us to modify
footprints, e.g. by adding a "Pin 1" marker.
Signed-off-by: Sean Cross <sean@xobs.io>
