I got the first assembled board and it works! Rev A! First try!

The uZed is running Linux and blinking an LED.

https://www.dropbox.com/sh/hgetmk27k96sbza/AABuHr8llUYHjj_6b3yZGmT0a?dl=0

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

jlarkin@highlandsniptechnology.com wrote:

I got the first assembled board and it works! Rev A! First try!

The uZed is running Linux and blinking an LED.

https://www.dropbox.com/sh/hgetmk27k96sbza/AABuHr8llUYHjj_6b3yZGmT0a?dl=0

Congratulations.

We're in the midst of figuring out why the first-silicon bathymetric
lidar chips we've been evaluating don't seem to work. (They aren't
really our design, but we've been kibitzing a lot since the very
beginning, so we've had a a fair amount of input.)

Looks like the silicon vendor's models for their brand-new integrated
APD designs aren't up to snuff. The IC designer's simulations look
fine, of course. In any event, we have these 20V APDs that we can't
bias above two diode drops because something else starts sucking a lot
of current. :(

Razza fraza %&$@#&*!!

However, as Mehitabel used to say at such times, "Toujours gai, toujours
gai."

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Thu, 30 Jun 2022 16:23:25 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

jlarkin@highlandsniptechnology.com wrote:

I got the first assembled board and it works! Rev A! First try!

The uZed is running Linux and blinking an LED.

https://www.dropbox.com/sh/hgetmk27k96sbza/AABuHr8llUYHjj_6b3yZGmT0a?dl=0

Congratulations.

We're in the midst of figuring out why the first-silicon bathymetric
lidar chips we've been evaluating don't seem to work. (They aren't
really our design, but we've been kibitzing a lot since the very
beginning, so we've had a a fair amount of input.)

Looks like the silicon vendor's models for their brand-new integrated
APD designs aren't up to snuff. The IC designer's simulations look
fine, of course. In any event, we have these 20V APDs that we can't
bias above two diode drops because something else starts sucking a lot
of current. :(

Razza fraza %&$@#&*!!

However, as Mehitabel used to say at such times, "Toujours gai, toujours >gai."

Cheers

Phil Hobbs

1.2 volts sounds a bit low for avalanche breakdown.

We found a mistake on the controller board: an FPGA pin can't do the
MOSI thing we wanted. One blue wire, a grim tragedy. Fortunately we
can hide it under the microZed.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

jlarkin@highlandsniptechnology.com wrote:

On Thu, 30 Jun 2022 16:23:25 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

jlarkin@highlandsniptechnology.com wrote:

I got the first assembled board and it works! Rev A! First try!

The uZed is running Linux and blinking an LED.

https://www.dropbox.com/sh/hgetmk27k96sbza/AABuHr8llUYHjj_6b3yZGmT0a?dl=0 >>>

Congratulations.

We're in the midst of figuring out why the first-silicon
bathymetric lidar chips we've been evaluating don't seem to work.
(They aren't really our design, but we've been kibitzing a lot
since the very beginning, so we've had a a fair amount of input.)

Looks like the silicon vendor's models for their brand-new
integrated APD designs aren't up to snuff. The IC designer's
simulations look fine, of course. In any event, we have these 20V
APDs that we can't bias above two diode drops because something
else starts sucking a lot of current. :(

Razza fraza %&$@#&*!!

However, as Mehitabel used to say at such times, "Toujours gai,
toujours gai."

1.2 volts sounds a bit low for avalanche breakdown.

It looks like there's some unsuspected silicon connection between the
substrate (APD anode, nominally about -18V) and some net called GND_I,
which is where ESD fault currents get dumped.

The current isn't going to VSS, VDD, or any of the chip inputs, just GND_I.

We found a mistake on the controller board: an FPGA pin can't do the
MOSI thing we wanted. One blue wire, a grim tragedy. Fortunately we
can hide it under the microZed.

The rug only has to be big enough for the amount of dust you actually
have. ;)

Cheers

Phil Hobbs




--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)