Now that is slick. Blink sketch successfully uploaded!

Thank you guys very much, I learned so much in this thread!!

Derp. Alright, just reflashed the bootloader.

Now when I bring the reset pin to ground, the Arduino Leonardo briefly (for about 2 seconds) changes to COM9, then back to COM8. There are no new COM ports in the Tools > Serial port menu.

How do I keep it at that COM9 port so I can program it?

My board does not have a reset button (I posted PCBs and schematics at least once in this thread, if you want to reference them).

Only one COM port was installed and it is "Arduino Leonardo (COM8)". When I unplug it and plug it back in, same serial port. When I uninstall that device and then plug it back in, it is reinstalled with the same COM port.

I tried to use a jumper wire to touch the reset pin to ground, and caused my computer to think it was disconnected and reconnected. But it still came up with the same COM8 port, nothing else.

Can I do this without a reset button?

I removed the the USB connector and soldered the wires from a hacked USB cable onto the pads. Now when I plug in the USB cable my computer recognizes it just fine. I get a USB composite device and a USB input device in my Device Manager.

After I installed the Arduino Leonardo drivers from the Arduino drivers folder I get an Arduino Leonardo device on COM8, which is recognized by the Arduino IDE.

However, when I try to upload the Blink sketch via the Arduino IDE, the COM8 port is dropped and the upload fails. I get the following error:

Code:

Binary sketch size: 4,826 bytes (of a 28,672 byte maximum)
processing.app.debug.RunnerException: Couldn’t find a Leonardo on the selected port. Check that you have the correct port selected.  If it is correct, try pressing the board's reset button after initiating the upload.
at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:152)
at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67)
at processing.app.Sketch.upload(Sketch.java:1671)
at processing.app.Sketch.exportApplet(Sketch.java:1627)
at processing.app.Sketch.exportApplet(Sketch.java:1599)
at processing.app.Editor$DefaultExportHandler.run(Editor.java:2380)
at java.lang.Thread.run(Thread.java:619)

What is going on now?

I've gotten pretty good at passives down to 0805, SOT-3, TSSOP and TQFP, but with parts that have large pads for mechanical strength (DC power jacks, JST, USB) I can generally get them on, but not off. However I set my soldering station temperature I seem to either have it too hot or too cold for desoldering those huge pads. Oh well, it's a prototype...just an expensive one :S

Those SMD connectors are a pain to solder! Definitely switching it over to the PTH variety for the next revision to make it easier on myself.

I have a pile of extra USB cables, I'll try to hack one apart and solder the wires directly to the board.

Have any tips for desoldering the thing from the board? I always seem to take the pads off the PCB when I try to get connectors like this off.

Yes, check the comment directly above yours. Measured the same voltage before and after fuse.

When powered via the USBtinyISP, I measure a solid 5V at UVCC and on both sides of the fuse.

When powered via USB cord, I measure ~1.6V at the same points.

UVCC is indeed tied to VBUS and VCC, as seen in the schematic posted just above.

I've attached a picture of the PCB design for reference.

Could the 0.1uF UCAP capacitor (instead of 1uF) be the culprit?

Oh, and there is a 0.1uF capacitor going to ground from pin 6 already. All of the other ATMega32u4 board schematics I could find had a 0.1uF, not a 1uF. Attached the schematic.

Edit: Oh no!! I just checked all the schematics again, and found that only Adafruit's 32u4 breakout has a 0.1uF to ground, all the others have 1uF! Holy smokes that's something.

For my own education, can someone help me understand what this UCAP capacitor does, and why the value may be accounting for this behavior?

When I power my board using the USBtinyISP only, I am able to measure 3.2V on pin 6 just fine.

When I power my board only using the USB connection, I get -0.4V! Only 1.6V on pin 2 (UVcc).

This seems to indicate that the USB mini B jack is not soldered right or bad in some other way.

I've attached a couple of photos of the soldering job, if that helps.

Haha, derp. No more continuity checking when power is on. Got it

I was able to successfully upload the Blink sketch just by selecting the File > Upload Using Programmer tool. Worked like a charm.

So it looks like something is off with my USB circuit. I used an SMD USB mini-B connector, which was a big pain to solder. I reflowed each of the joints and re-checked the pads and pins with the continuity tester and it looks like each is solidly connected. I still have a hunch that there is something off about the USB circuit, but I don't know what.

What in the world...I have a weird gremlin now, not sure how to fix.

I do not have an oscilloscope, but I do have a basic multimeter with the beeping circuit tester.

When the board is disconnected, the board checks out just fine. I use my circuit tester to check every ground connection and make sure that nothing is connected that shouldn't be.

When I plug the board in, I check the same connections again and it seems that the ground and +5V lines are connected! This behavior persists for a little while after the board is disconnected before going back to normal.

I was really, really careful to check all of my connections, and triple-checked my soldering of the USB mini-B jack, and it all looks OK. But when it is powered on, I have problems.

While I was testing the board with the USB cable plugged in, I actually saw my computer intermittently trying to install the Arduino Leonardo device for brief moments. So the bootloader did flash correctly, but something else is preventing the board from working properly.

Any ideas?

Yep, I regularly use these cables for other electronics projects. I tried three more cables, and same result each time.

I grabbed a USBtinyISP from Adafruit last week, then used it today to flash the Leonardo bootloader onto my custom ATMega32u4 PCB project board (schematic here: http://jason-webb.info/wp-content/uploads/2013/04/openSip+Puff-schematic.png).

I made sure to select "Arduino Leonardo" from the Toosl > Board menu, then select USBtinyISP from the Tools > Programmer menu. I hit the Tools > Burn bootloader option and let it go. It took a minute, but I eventually got a message saying "Done burning bootloader."

So I disconnected the USBtinyISP and plugged in my board via a USB cord. Windows does not make any noises, and the Device Manager shows nothing new. I see no new COM ports under the Tools > Serial Port menu. Did I do something wrong?

How do I upload new sketches my board? Do I have to use the USBtinyISP every time, or can I use the USB port?

I'm curious if there are any known bootloaders that would allow me to upload standard Arduino sketches that take advantage of the ATMega32u4's USB HID capabilities for MIDI? Leonardo only seems to do keyboard and mouse, not MIDI, and the Teensy and LUFA bootloaders look a bit more complicated than I need. Any other options?