look for the FTDI232, available as bare chip or in modules.|
This chip is very easy to use, because it's delivered with a number of free windows drivers.
As for the max current, normally it's limited to 100 mA,
to be able to draw upto 500 mA,
you need 2 things extra:
- an eprom, attached to the FTDI, to tell the computer that's a high power device
- a FET to switch on the high power, after the USB chip is initialized
All schematics can be found on the FTDI site.
Dave Mucha wrote:
Hi all, I was looking at the serial, 9 pin to USB connector cables. Seems these unit might offer an added benefit, that is, if they work well. It would seem that the power availabe on a USB port could be used to power some small circuit. >From what I have read, the USB offers about 2.5 watts of power, or up to about 500mA. Not too shabby for a simple PIC unit? Am I on a track that might work ? I assume I would have to modify the USB cable that I get, but at the same time, mu current project is only a few chips.... Dave to unsubscribe, go to http://www.yahoogroups.com and follow the instructions