Olimex Support Forum

OLinuXino Android / Linux boards and System On Modules => A13 => Topic started by: Jules on May 05, 2013, 02:48:23 AM

Title: GPIO drive strength?
Post by: Jules on May 05, 2013, 02:48:23 AM
Does anyone have any figures for how strong the drive on GPIO output pins from the A13 is?  The datasheet is somewhat vague (it has a column for drive strength, but it isn't filled in), and the only thing I've seen that is maybe relevant is in the pinctrl file from recent kernels (see http://code.ohloh.net/file?fid=E-kEIXaC1RPD8Gtdoc2d9R6m8_8&cid=6NGO2C2fa5k&s=&browser=Default#L0 ) which appears to suggest that 40mA is available.  Is this correct?  And if so does it require specific configuration, or is this available by default? (I'm using a Debian image downloaded from the wiki, if it's relevant)
Title: Re: GPIO drive strength?
Post by: Jules on May 16, 2013, 09:26:15 PM
The documentation on 'fex' files ( http://linux-sunxi.org/Fex_Guide#lcd.5B0.2F1.5D_configuration ) also suggests that 40 mA is available (if the pin is configured appropriately), so this seems to be reasonably certain.  Is anyone aware of any limits on the number of pins that could be used to drive current this high?
Title: Re: GPIO drive strength?
Post by: JohnS on May 16, 2013, 10:20:14 PM
I suggest very few!  Be ready with a cooler and maybe run stress tests like cpuburn

John