So I got my prototype board put together…
But I can’t get it to respond.
Because I ordered the wrong footprint part I had to improvise on USB.
Windows device manager detects absolutely nothing.
I’ve powered a TH G30 off of the 3.3v rail and it works fine.
I meticulously traced every pin on the processor to it’s destination and everything traces fine. I had to pull the first G30 and replace it as there was solder bridging from the first reflow on the inside of the pins I couldn’t clean up without removing it. The second chip has good contacts on every single pin (took 2 hours to trace everything) and there is no bridging.
My 12mhz crystal was not working whatosever - nothing is being put out on XTAL_OUT. I ended up removing the 12mhz crystal, and capacitors, and hard wiring a shunt from XTAL-IN on the G30 TH board to the processor to get it a clock signal. That shows up fine on the scope now.
But no matter what I do I can’t get anything to show up on device manager when I plug in USB. I verified the pinouts on the USB line up with the correct pins on the MCU.
The G30 TH board shows up as “EMX” when I plug it in. The G30 prototype board, absolutely nothing.
I don’t have a computer handy with a serial port - and the USB to serial cable I had on hand is incompatible with Windows 10. I plan on buliding a computer from scratch today out of boneyard parts to get a win7 / serial capable system up so I can get access to the COM headers.
But it looks like this just isn’t working. I’ve verified 3.3v is good and going to all pins it is supposed to go to. I’ve triple checked the caps and pullup resistors, and the 4.7 cap on the pin that needs it. My voltage regulators are working good - I can use them to power the TH module no problem on a breadboard next to this one. TLV1117 3.3v regulator is driven off of an L7805CDT 5v regulator which is being powered by a 9v DC power plug on the 2.5 mm jack. All of that works as expected.
Not really sure where to go with troubleshooting from here. I basically mirrored the G30 dev board schematic when designing this, with the addition of a pair of GPIO extenders added to be able to control 32 relays via breakout headers. It’s not an overly complex design.
Any ideas? I worked on this for 12 hours yesterday and made no headway.
(Also I ended up getting a USB port harvested and soldered directly to the board, eliminating that hack job of a USB breakout, it checks out on logic tests)