Another 32U4 design - need extra eyes

After the [last failure, I made a revision to the design around the controller. Missing from the original design were some indicator LEDs ad well as grounding the HWB pin. This time I followed the Arduino Micro’s design a bit closer, got rid of a components or two, and added others. I need some extra eyes to comb over this and check for faults or other missing bits and pieces before I commit to starting the layout process and getting new boards made. If you don’t mind …](Problems with 32U4 custom design - SparkFun Electronics Forum)

How about comparing your board to a arduino leonardo?

http://arduino.cc/en/Main/arduinoBoardLeonardo

waltr:
How about comparing your board to a arduino leonardo?

http://arduino.cc/en/Main/arduinoBoardLeonardo

The Leonardo and Micro are fairly similar. And considering that I have a much better track record with the Micro than I have with the Leonardo, I choose to follow the design of the former.

I’ve also discovered tonight that the test boards I made based on the above circuit, also don’t work with the Leonardo bootloader. They do the same exact thing, go into reset but never gets anything uploaded to them. On a whim I reflashed them with the Micro bootloader and that works, no problem. So maybe I’ll reset the fuses on the Leonardo board, upload the Micro bootloader see what happens. It doesn’t work right now anyway so I don’t have anything to lose here.

not sure about interrupts directly off of push buttons – switch bounce, multiple events etc.

bring hwb out to a test point so you can attach to it if need be

have you borrowed a scope yet and had a look at the previous xtal issue yet ?

have you tried the previous design with an 8MHz xtal ?

-mark

just spotted the end of your last posting - well done.

I normally put together a spreadsheet of manufacturers part number, schematic symbol and footprint then go through each item line by line and make sure all entries are correct.

anyway, forwards and upwards.

are you building these boards by hand, or are you paying an assy house ?

By hand for now. The final product is a POV stick. If there is enough interest, I’ll go the PCBA route.

markaren1:
not sure about interrupts directly off of push buttons – switch bounce, multiple events etc.

They work beautifully. You still need to work in the denounce logic but that’s trivial.

markaren1:
bring hwb out to a test point so you can attach to it if need be

Now that I understand what it does, it’s getting permanently grounded. It’s like that right now and the whole unit works. It cycles through reboots as I would expect it to. I have considered adding a slide switch to it but I’m still debating that. Not only is this package very small and space is at a premium, I’m not sure I can rely on the end user to remember to flip that when they need to. Permanently grounding it introduces a short delay when it power cycles (for it to go through its boot up sequence) but it’s nothing that’s getting on my nerves … yet.

markaren1:
have you borrowed a scope yet and had a look at the previous xtal issue yet ?

I’ve decided I’m going to get a DSO from SFE for now and eventually get a Tektronix. That was before I discovered the problem. Now I may wait and forego the DSO and get the Tektronix (only).

markaren1:
have you tried the previous design with an 8MHz xtal ?

I may but for a different reason …

By the way, when I said POV stick, it quite literally is. About 18" long, 192 LEDs, made to be spun around. I took pictures of me spinning the breadboard prototype version (breadboard with controller and SD reader is on a table with a 20’ long cable to the stick in my hand.) The first 8 in the top row are dynamically generated, the rest of them are all small images being read off of an SD card: http://goo.gl/Tzyxan