Hello All,

The project I have been working on is for a USB stick capable of receiving wireless signals and inputting keyboard commands into the PC, with the ATMEGA32u4 being at the heart of it all. Through research, I have found many iterations of the 32u4 being used as a standalone microcontroller, each with their differences. Linked to this post is my interpretation of those.

My question is, Is my schematic sufficient to safely run the microcontroller though the USB power supply? Have I missed any vital components, or in fact can I get away with less?

I will be uploading the operating code via the 6-pin header, and sole operation will be run though the USB power supply.


32u4 Test.JPG|783x505

If you want reliable operation, add a 0.1uF from every VCC and AVCC pin to Gnd. You can't put 5V into a 5V regulator and get 5V out. Delete the MIC5219.

Connect Vusb from the USB connector to a PTC Resettable fuse, and call that output VCC or 5V and connect the supply lines to it.

You show inductor symbols where resistors are normally used. That would likely have a poor impact on the D+ and D- lines if you actually installed inductors there. Same for the LED.

nrf24L01, isn't that a 3.3V part? Perhaps it has 5V tolerant IO, but I'm pretty sure most modules expect 3.3V for power. You'll probably need a 10uF cap mounted at its VCC pin also, to handle the large burts of current it needs during transmitting.

Truly fantastic information CrossRoads! I'll put the new schematic together!