Notices by poleguy looking for lost tools (poleguy@mastodon.social)

@badnetmask Thanks, no-longer-random reader!
I do use cloud-init to set up the ssh keys to get in to the vm. But I'm trying to have the vm then load sshfs mounts from the host. For that I need to put the vm keys back on the host. I did not see a way to do this via cloud-init. Even if it had that capability it would seem like 'feature creep.' That goes beyond 'init' doesn't it?

I just learned about virsh and wish I had known of it earlier. It works. Just looking to find out what others do.

This runs in 2m:24s on my machine. Who can run it to confirm it works "not on my machine?"

This week I went meta: tested the installer of the test sim of the telemetry used to test the product. I'll call that a test-test test.

I now have one automated script.

completely means:
* create vm from scratch
* ssh keys in both directions
* apt dependencies
* mount non-apt bits from host
+ vivado
+ cvc64
* self checking sim

https://github.com/poleguy/protonpack/blob/main/scripts/test_install.sh

#automation #python #vm #testing #linux #fpga

Just pushed some updates. I have posted the #verilog serial link code. This involved getting a set of scripts for simulation set up.

If anybody is interested in helping on this project, I'd love to have somebody try to follow the readme.md to install the prerequisites and run the ./run_sim script.

The goal would be to take notes and flesh out what things aren't in the prerequisite list and how to install them.

I'd be happy to do the same for somebody else's project.

#fpga #reproducibility

I'm so proud! #Sennheiser never would have allowed a #garage-built #proton-pack to make it in to their behind-the-scenes video! (That's me starting at 2:36)

https://www.youtube.com/watch?v=tZZmv2LQ-Es

For contrast, don't miss the Sennheiser #Spectera video.

https://www.youtube.com/watch?v=Qvi36Lq4eHc

#Shure #IEM #wireless #electronics #telemetry

I'm doing the next generation protonpack #fpga telemetry system as an #opensource #openhardware design.

Team #mastodon will help me out, right?

https://github.com/poleguy/protonpack/

I have five lines of bash to set-up ssh keys. At least they are easy to understand. Is this normal practice?
I could use #ansible for this, but that creates another dependency. Is that what people do?

I don't want to argue about the safety of wget, github or |bash. You can't argue that it's effective. How do _you_ solve this chicken-vs-egg problem?

#automation #python #vm #testing #linux #fpga

Are there things in this script that can be eliminated?

Can virt-install be set to wait till the install is done and the vm is ready and return a pass/fail?

I don't like polling with 'virsh domifaddr' to find the IP address, but it works. How do other people get the IP address of a newly created VM?

I don't like polling a log file for a string match to wait for completion of cloud-init to avoid potential race conditions. How do people know their VM's are actually running?

I'd love your critique of my approach. (Yes you, random reader!)

This is a holy grail that I've searched for numerous times. I started on windows (10+ years ago) and the ability to automate was abysmal.

It's much nicer now with cloud images, virt-installer, python and linux. I decided to do it and within a few days on-and-off it is running fully automated.

How are other people doing this? (I suspect for most project the answer is they are not.)

#automation #python #vm #testing #linux #fpga

@whitequark @azonenberg The Wayne Gretzkys of baud rate.

@whitequark Our samtec rep seems to get a bonus based on how many free samples he hands out, so cost is not really a concern if I just need a couple.

But anything that requires a quote to get a price is hopefully never something that I specify on a board that I design. Oh well, no surprise really.

@whitequark @G_glop How much does this cost... hmmm... (What's the part number?)

Can confirm pin headers don't fail at 10 MHz. I currently have 800Mbps data running on a 0.100" pitch header on my bench:

https://mastodon.social/@poleguy/114512955425762180

I did solder in a 0201 differential termination and added 4 dB attenuation to get the voltage down within spec, because the input signals are HSTL and the receiver is set to LVDS.

If cheap enough these cables could make cheap/fast board-to-board serial links possible.

@jpm @whitequark I effectively got coax working with dupont connectors at 800 Mbps last week.

https://mastodon.social/@poleguy/114512955425762180

Remember they call them "circuits" because the signal must travel in complete loops (circles). Interestingly the signal never travels down the wire and back in a different wire. That's a mistake due to how we draw schematics and name signals, etc. The signal actually travels from the source to the destination in both halves of the circuit at the same time.

@jpm @whitequark (I know I'm preaching to some of the choir here)

But the twisted gnd is so effective because without it you only built half the circuit. Without a carefully run ground the other half of your circuit is more likely producing radio signals (literally) than doing what you drew in your schematic.

The mistake is that we don't draw circuits on schematics. We draw half circuits and a gnd symbol. It's not magic. But signals don't travel in wires but in the field between conductors.

@whitequark "ceremony..." that resonates. Well, I appreciate you humoring my line of inquisition as far as we took it. It reaffirmed my sense that it was not a route likely to pay off with any practical value.

@whitequark I feel a bit sad that gdb is seemingly ossified so hard that spinning up a new architecture/ language/ machine code is essentially harder than reinventing everything from scratch. But if someone like you won't even endorse it, it is not worth pursuing even as a personal challenge. My youthful idealism is dashed. :-(

@whitequark yes. I implemented a step debugger, breakpoints and memory inspection when we designed the processor originally. In reality the code is all real time dsp, so debugging is mostly done in rtl/cocotb sim where we just spit out a trace file based on watching a variable and/or program counter. Or we do it in hardware using telemetry over a gigabit serial link where we can stream out whatever state we need to monitor. Or we use one channel of the audio output to monitor an internal node.

@whitequark done.

@whitequark This does not surprise me. But in my previous attempt I could not find even a basic list of steps like this.

I can disassemble/write the machine code. But I don't know how to do so "for gdb".

We do not use elf. The code is just a binary file with machine code that gets loaded into an FPGA RAM.

We have not written a compiler. Everything is written in assembly. I would aim for assembly level debug only. I wonder if this makes it easier or harder.

Tedious/thankless sounds right.

@whitequark You mean there isn't a hello world? If so, that makes me feel good that I didn't just fail to find it. :-)

I probably don't have the terminology right. What does it mean to "have gdb" for my "DSP target"?

I presume the steps look something like write some code on the PC that translates between what gdb needs to work and what my serial-cli can provide. (?!).

This is a custom FPGA, I presume there is also some sort of definition for my architecture/assembly/machine code needed?

@whitequark I'm not confident I know exactly which pieces you've been working on here. But I have dreamed to do something like this for a custom DSP inside an FPGA at work. I'm not afraid of getting my hands dirty. But the last time I tried to find the "hello-world tutorial" for connecting gdb to an arbitrary device I didn't get very far. I'd love to connect it via our existing cli/debug interface (serial-usb). I've implemented everything needed to do step debugging in the hdl, but no gdb yet.

@whitequark just today I wished I could open vivado from my other machine. But what I really wanted was to connect to the session that was already open. I ended up walking out to the lab. I actually have an x2go session open with vivado as well, but x2go doesn't do a good job sharing the local desktop when you have many physical monitors hooked up. And it really doesn't like the Dvorak keyboard layout. I hadn't thought of steam.