NASR-M base controller works!
I’ve started populating the board, and the base controller worked. Although my long-term plan is to use a Zephyr, for simplicity, I resorted to a quick stub firmware written with STM32Cube that activates the ATX PSU and blinks the status LED. I’ve got the (primary) power!
The ever-growing “lessons learned” list has been updated with the following:
NASR-M clock generator preliminary config
The heart of the NASR-M carrier boards is the LMK03328 clock generator. It's an ultra-low noise and high-performance clock generator with two PLLs and eight outputs. The outputs can be set to single-ended or differential with an adjustable voltage level. The chip can switch between two reference inputs and is configured with I2C. In my case, the main reference input is the onboard TCXO, and the secondary is an external reference.
Interactive HTML BOM plugin for KiCad
Those of you who have assembled a complex board manually know how much time it takes to prepare components and cross-check them against BOM lists while soldering chips onto the board. Usually, I prepare a few paper lists for that purpose and cross out soldered components one by one. However, it’s not as fast as you may think. My silkscreen designators aren’t perfect, so I still occasionally have to check the schema to continue. Today, I was looking for a better way to generate the BOM for assembly and found “Interactive HTML BOM plugin for KiCad”.
Syncthing
I am thoroughly amazed by Syncthing. Before that, I had used other options to synchronize files across my desktop machines, but Syncthing beats them all in terms of configuration simplicity and ease of use.
X-Ray BGA inspection photos
Ever wondered what BGA X-Ray inspection reports look like? Here is a sample from JLCPCB. It cost me around $2. Photos are under the cut.
NASR-M first prototype production
Yesterday, I sent the initial NASR-M prototype for production to JLCPCB. Hoping there will be no obvious blockers and I'll be able to bootstrap Linux with no re-spins. I want to bring the board up circuit by circuit to know precisely what works and what doesn't.
Goot RX-802AS soldering station
I've got a new soldering station - Goot RX-802AS. It might not have the best thermal recovery, especially compared to much more expensive temperature-controlled stations, but it's one of the leaders in its price class, and has its own perks.
howto bypass the corporate firewall
This article provides a brief guide on circumventing the corporate firewall using an SSL tunnel. Why bother? Sometimes it blocks legitimate resources I need to access, and it is slow. Requesting a whitelist for each domain individually is time-consuming, so I decided to explore alternative methods. Most corporate firewalls are designed to be cost-effective, not maximally efficient. To bypass the restrictions, we could use a simple SSH tunnel wrapped inside the HTTPS session to the Internet server. Why do we use SSH inside the SSL tunnel? Some corporate firewalls perform man-in-the-middle attack by providing custom certificates installed on company computers, so that browsers would not complain about an untrusted certificate in the chain. Correctly configured SSH with public key authentication is used to mitigate the man-in-the-middle on the corporate side.