bosskardo
Junior Member level 2
I was thinking if it would be possible to get 5V power from a USB connection that connects AT90USBKey to the computer.
http://www.atmel.com/Images/doc7627.pdf
The board converts the voltage to 3,3V but could I connect a 5V line of my circuit to the AT90USBKey board before the voltage converter?
Would this also possibly cause problems that the AT90USBKey board doesn't get enough current if my circuit draws too much?
On a little different theme:
http://www.usbmadesimple.co.uk/ums_2.htm
This says that USB supplys max 100mA if it isn't configured. What does that mean? I looked at my USB port properties and they all have max power at 500mA.
It also says that the device must reduce its current draw to 2,5mA if there is no activity on the bus. What would happen if I just tried to get power from USB power pin and left the others unconnected? Would I be able to draw current?
http://www.atmel.com/Images/doc7627.pdf
The board converts the voltage to 3,3V but could I connect a 5V line of my circuit to the AT90USBKey board before the voltage converter?
Would this also possibly cause problems that the AT90USBKey board doesn't get enough current if my circuit draws too much?
On a little different theme:
http://www.usbmadesimple.co.uk/ums_2.htm
This says that USB supplys max 100mA if it isn't configured. What does that mean? I looked at my USB port properties and they all have max power at 500mA.
It also says that the device must reduce its current draw to 2,5mA if there is no activity on the bus. What would happen if I just tried to get power from USB power pin and left the others unconnected? Would I be able to draw current?