MAX3421E not communicating

[lluth]

I've put this schematic together for a USB MIDI Host using an ATMEGA328P and the MAX3421E.

While the 328 will run a blink code sending MIDI messages to the output successfully, the same cannot be said about running the MIDI Converter code from the MAX3421E USB inputs. Keep in mind I've built this on a breadboard and the MAX3421E is on an SMD breakout board.

Am I missing any vital connections? I tested the 328 with the Pro Mini Host Shield and it worked perfectly so all I seem to have done is encorperate the sheild's schematic into my design.

[customcontroller]

Looks like the CPU using 5V logic levels is directly connected to the max3421e using uses 3.3 logic levels. Either use logic level converters or use 328 running at 3.3V.

[lluth]

Unfortunately I've had them both run at 3.3v too and that's no bueno

[gilshultz]

I’ll guess that you first ran the components at 5V, then tried 3.3V, and now they don’t work. It’s likely that you damaged the 3.3V component. Over-voltage typically causes damage, but determining exactly what part is affected can be difficult and costly.