On Jun 15, 2010, at 22:14, m...@gmail.com wrote:
>> What is the context of your question? Do you want to
go from 3.3V to
>> 5V or from 5V to 3.3V?
>>
>> Do you already have a board design for your 5509A? Do you need to
>> take the 5V nominal USB voltage down to 3.3V for the DSP?
>>
> The supply voltage of PC is 5v.... Th voltage of the DSP USB is
> 3.3v... If we interface DSP USB with system's USB, will it not
> damage the device?... Since the operating voltage of DSP is 3.3 to
> 3.6v....
It seems like you're saying that you have not designed your board
yet. I suggest that you look on the Texas Instruments site for some
of the reference schematics. They show a number of options for
making a board with USB and the 5509A.
In general, though, USB provides anywhere from 4.0V to 5.25V, and so
it is expected that you place a 3.3V regulator, usually of the LDO
variety, on your circuit board to power 3.3V parts like the DSP. The
DSP wires D+ and D- directly to the USB connector, but the VUSB
signal must only connect to the input of the LDO regulator. From
there, the output of the regulator connects to the DSP. It can be
confusing, since the DSP has multiple 3.3V input pins, including one
specifically for USB. After you've handled the power correctly,
there are also some requirements for the D+ and D- signals, including
series resistance, capacitive filtering, etc.
I think most of your questions will be answered with the schematics
for the evaluation boards.
Brian Willoughby
Sound Consulting
Interfacing TMS320VC5509A with PC
Started by ●June 13, 2010
Reply by ●June 16, 20102010-06-16
Reply by ●June 20, 20102010-06-20
