Is there a third Teensy 4.0 breakout board?

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@mjs513 - Same link, but when it adds it to the Cart - there is a a set of possible options, like supper swift...

One of them is: 2 oz copper, 0.8mm thickness

Which is what I forgot to check, but noticed it in my order receipt and went Oops, and quickly put hold on order and emailed them...

Yeah I just reordered the boards without USB and looked closely at the following screens and this time I checked off the box for 0.8mm. Guess we will see what happens in a few weeks.
 
Sorry I was busy this weekend with something else.

@kurt - I bought microSDs in a reel from a manufacturer, one of our suppliers. I don't know where you can get it. I could not find it on eBay. If you don't solder 2 mounting pads in the back, you may solder the same one being used on Teensy 3.5 made by Hirose.

@mjs513 - Sorry that your board was not routed. It should not be your fault. It's an Oshpark's random error. I also specified in a Gerber file that those cutout holes much be routed. The routing has nothing to do with the thickness. In either thickness, 0.8mm or 1.6mm, those cutout holes should be routed.
I think that your boards may still be usable. If you drill a 0.050" hole (#55 drill bit) near a castellated pad, it will open up a small area to solder. If you don't have a center punch, you can drill a very small pilot hole to secure the location for the #55 drill bit.

Drill_15_of_#55_holes.png
 
Sigh, I have the worst luck with soldering. As I mentioned, I soldered the first board, trying to solder in stacking headers by having some space between the header and the board. It didn't go so well, so I cut off the stacking header, and unsolder the pins. But I lift the plating from the top part of several pins. So I convert the board into a normal Teensy, soldering the header on the bottom, but I won't be able to put castlelatted boards on that.

I got out a second board, and soldered it up just using normal pins, and it seemed to work. However, I had several pins on the right side that were not properly soldered in (3.3v, pins 22-18, and pin 16). So I attempted to redo the solder connections. But now I presumably have a solder bridge somewhere, and the Teensy 4 is getting hot to the touch and quitting after a few minutes. Tomorrow, I will attempt to unsolder all of the connections, and redo them. But I suspect the issue was I probably damaged the board having the solder gun at max as I was removing some globs of solder and I probably kept the iron on the board too long, and reflowed some solder on the PCB itself and made a short.
 
I have essentially no surface mount soldering experience, but I thought I would add a couple of comments for others in my situation. 402 sized components are so small that I would call them 'dust'. I'm sure that in expert hands with a clean room they can be used to produce elegantly small circuits, but I cannot imagine manipulating them with tweezers. Pick a bigger size.

Many microSD card sockets are too wide to work well. It would be great to have a part number that avoided the problem. The thought I have (since I have parts that are too wide) is that the pins adjacent to the microSD socket could be pushed flush with the PCB before soldering, so that the socket does not bridge the pins.
 
You are right, the 0402 is more difficult than other sizes, only should be used when you don't have other sizes available.

I buy microSD in a reel from a Chinese manufacturer that only sells to their domestic market. They don't even speak English. Their part# is meaningless. 520A, what's the 520A? where can you get 520A from anywhere?

The same micro SD that is used on Teensy 3.6 can be soldered on this breakout board. I just tried one. It seems be OK, no shorts are found. see the picture.
Only problem is that the door switch will not work.

Micro_SD.jpg

PCB has solder mask to prevent door switch contacts from shorting with any trace. If you want to make it better, just add a piece of Kapton tape under the switch contacts before soldering the micro SD.
 
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