Page 1 of 1
Interface slow 5V signals
Posted: Tue May 11, 2010 2:14 pm
by skoe
Can I connect slow 5V signals using a series resistor of about 1 k to the XMOS' I/O ports? Will the clipping diodes be enough in this case to protect the inputs? It's just a test circuit, nevertheless I don't want to blow up my XMOS.
Regards,
Thomas
Re: Interface slow 5V signals
Posted: Tue May 11, 2010 4:14 pm
by leon_heller
Inputs are 5V compatible, see the data sheet.
Re: Interface slow 5V signals
Posted: Tue May 11, 2010 5:28 pm
by Woody
leon_heller wrote:Inputs are 5V compatible, see the data sheet.
Only XS1-G devices have 5V tolerant inputs. XS1-L parts have a maximum input voltage of 3.6V (~3.3+10%).
As Leon says, check the datasheets.
Re: Interface slow 5V signals
Posted: Tue May 11, 2010 5:39 pm
by leon_heller
I checked the data sheet I had for the XS1-L1, and that gave 5.5V as the maximum. The latest version gives 3.6V.
A resistor should be OK for the XS1-L1, I've seen one used with other devices.
Re: Interface slow 5V signals
Posted: Tue May 11, 2010 10:45 pm
by skoe
Thanks!
There must be a reason they corrected it down to 3.6 V in the latest revision :) I'll add another resistor per pin to build a voltage divider, just to be on the safe side.