[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: gpio question on Axis82



Hi,

I think there has been a problem in the schematics which caused the power 
supply to D25 to be unconnected. Check that pin 14 on D25 has 3.3V. 
Otherwise connect the pin to some other pin with 3.3V.

Best Regards
/Mikael

PS. The NAND gates in D25 is connected as inverters. If D25 has power
and GND correctly connected and still doesn't invert the signals,
it must be broken. DS.


-----Original Message-----
From: owner-dev-etrax@xxxxxxx.com">mailto:owner-dev-etrax@xxxxxxx.com] On Behalf Of Kevin Wooley
Sent: Wednesday, June 11, 2003 5:16 AM
To: dev-etrax
Subject: Re: gpio question on Axis82


OK, it turns out that the pins are working correctly on the ETRAX, but the NAND gate - D25 on the devboard 82 doesn't seem to be behaving properly.  according to the schematic, the output pins shouldn't have any resistors connected, but they certainly don't change when the inputs change.  Could this be a problem with the chip or is there something in the schematic that I'm missing?

Kevin Wooley wrote:
> 
> I'd like to use the gpio pins g1-g4, which are available through a 
> NAND gate on header pinx X23.
> 
> using this basic test program below, the pins don't seem to change.  
> The pins are multiplexed to a bunch of devices, but I'm pretty sure 
> I've disabled everything in the kernel config except for Shared-RAM, 
> sicne I'm not sure where to configure that.  According to the 
> schematic, the pins aren't connected to anything else, so I think they 
> should be available for use.  How do I ensure that Shared-RAM is 
> disabled?  is this the same thing as SDRAM (I don't think so).  Is 
> there something else I need to do?
> 
> thanks,
> 
>         Kevin
>