RTEMS on Beaglebone Black

Mr. Andrei Chichak groups at chichak.ca
Wed Jul 29 05:15:11 UTC 2015


I don’t know if this is the answer, but a lot of the GPIOs that you can’t get to work are wired to a 4GB NAND eMMC chip using the MMC1 bus.

GPIO1_16 is tied to GPIO2_0 through R160 and R161 as shown on page 3 of the schematics. I have no idea why that would be.

A


> On 2015-July-28, at 21:30, Angelo Fraietta <newsgroups at smartcontroller.com.au> wrote:
> 
> I have done some more tests to check whether all inputs actually work.
> I set all as inputs like this in the init
>   *(unsigned long *)(GPIO0_ADDR+OE_ADDR) = 0xFFFFFFFF;
>   *(unsigned long *)(GPIO1_ADDR+OE_ADDR) = 0xFFFFFFFF;
>   *(unsigned long *)(GPIO2_ADDR+OE_ADDR) = 0xFFFFFFFF;
>   *(unsigned long *)(GPIO3_ADDR+OE_ADDR) = 0xFFFFFFFF;
> 
> And read them in a task while switching the pins between 1 and zero
> 
>       data_0 = *(unsigned long *)(GPIO0_ADDR+GPIO_DATAIN);
>       data_1 = *(unsigned long *)(GPIO1_ADDR+GPIO_DATAIN);
>       data_2 = *(unsigned long *)(GPIO2_ADDR+GPIO_DATAIN);
>       data_3 = *(unsigned long *)(GPIO3_ADDR+GPIO_DATAIN);
> 
> 
> I found that GPIO1_0 to GPIO1_3 did not work
> I found that GPIO1_30 and GPIO1_31 did not work
> I found that GPIO0_4 and GPIO0_5 did not work
> 
> I found GPIO1_16 is actually GPIO2_0 - which is very strange as all the other GPIO2 are on P8
> I found none of GPIO3 read a value
> 
> Anyone have have any suggestions? Maybe an incorrect address for GPIO3?
> #define GPIO0_ADDR 0x44E07000
> #define GPIO1_ADDR 0x4804C000
> #define GPIO2_ADDR 0x481AC000
> #define GPIO3_ADDR 0x481AF000
> 
> Thanks
> 
> On Wed, Jul 29, 2015 at 11:49 AM, Chris Johns <chrisj at rtems.org <mailto:chrisj at rtems.org>> wrote:
> On 29/07/2015 2:01 am, Joel Sherrill wrote:
> >
> >
> > On 7/28/2015 8:39 AM, Mr. Andrei Chichak wrote:
> >> Hey Angelo,
> >>
> >> If you have about an hour, listen to the embedded.fm <http://embedded.fm/> podcast #110
> >> (www.embedded.fm <http://www.embedded.fm/> <http://www.embedded.fm <http://www.embedded.fm/>> or iTunes). They talk with
> >> Jason Kridner of Beagleboard.org <http://Beagleboard.org <http://beagleboard.org/>>, also from
> >> TI. He wants people to send him queries about the Beagle Boards, like
> >> your pinout questions.
> >>
> >> RTEMS even comes up in the conversation.
> >>
> >
> > I saw a tweet on this last week. I need to listen to Jason also.
> > He is a nice guy and the embedded.fm <http://embedded.fm/> podcast is a great resource.
> >
> 
> Great podcast.
> 
> Chris
> 

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