Re: [Usbpicprog-technical] USB electrical characteristics

[Frans S. <fra...@gm...>]

Hi Francesco,

Sorry for not responding, I just opened these mailing lists and discovered
that I forgot to subscribe myself!
Don't worry too much about the current consumption of usbpicprog, it will
draw 50mA max. It can also work from 4.2V.

What you do have to worry about is connecting a target board which is
powered by usbpicprog. If that one draws more than about 300mA, give it his
own powersupply of 5V.
Because of the diode in the VDD connection, it is allowed to use a 5V power
supply (but don't use a lower voltage than 4.5V when usbpicprog is trying to
power up the target board)

Cheers,

Frans

> Hi all,
> I looked at the USB specs taken from usb.org (file usb_20.pdf,
> paragraph 7.2.1) and I've found that any device attached to a USB port
> should be able to work with a Vbus down to 4.4V and is allowed to draw a
> maximum of 100mA upon power-up and a maximum of 500mA after
configuration...
>
> Are those data correct?
>
> How much current does usbpicprog draws from the USB port?
>
> Thanks,
> Francesco