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SB72 GPIO w SPI Pins

Posted: Mon Aug 22, 2011 6:38 am
by rhopf1
Need that one more pin thing, using PC0..PC3 but not any SPI functions. So can the 4 SPI pins be used as GPIO? (wish there were schematics available to answer this myself).

Re: SB72 GPIO w SPI Pins

Posted: Mon Aug 22, 2011 7:26 am
by Ridgeglider
I don't use the SB72 so I'm not familiar with the details of which pins are brought out on that board, but for most of the platforms the answer would be yes, you can use dedicated pins for other GPIO uses as long as they are brought out to a header and if there is a jumper that's sometimes required to disconnect it from a (standard) dedicated use.

See http://www.netburner.com/downloads/mod5 ... -PinIO.pdf
for details of how the pin class provides one way to configure the pins to various available functions.

For details about jumpers and headers, you should have schematics for any licensed platforms in either C:\nburn\docs\platform\schematics or C:\nburn\docs\platform.

Note that the SPI pins are usually used by the SD card, so reconfiguring them for other uses may mean that SD card access is impacted...

Re: SB72 GPIO w SPI Pins

Posted: Mon Aug 22, 2011 9:54 am
by rnixon
I don't think its a schematic issue, since they would go directly to the processor. The question is whether or not the 5272 processor can make those pins work as gpio. I don't have an answer to that, but there is probably something in the freescale 5272 manual that would indicate that. Looking at the MOD5272 app notes at http://www.netburner.com/support/techni ... ments.html, it seems that the SPI chip selects can be used as gpio. But that's a different platform, so you would need to write some code based on the freescale manual register descriptions for your SB72.

Re: SB72 GPIO w SPI Pins

Posted: Mon Aug 22, 2011 10:56 am
by Ridgeglider
My mistake... Rnixon is right, I sent you info on the Mod5272, not the SB5272. However the following appnote indicates how to use the SPI pins as GPIO:

See the following appnote for setting PC0..PC3 as GPIO:
http://www.netburner.com/downloads/sb72 ... ration.pdf.

See page 10 of http://www.netburner.com/downloads/sb72 ... 1&view=Fit for the pinout of the J4 SPI connector.