Re: [Discuss-gnuradio] Using Sysfs to set a GPIO in Overo

[Philip Balister]

On 05/02/2012 08:16 AM, Sameh Yassin wrote:
> Dear P. Balister,
> I found that tutorial which explains very well how to create a GPIO folder 
> and set its direction
> http://www.avrfreaks.net/wiki/index.php/Documentation:Linux/GPIO#gpio-sysfs
> 
> 
> I searched for the misc GPIOs to make sure they are free and I'm pretty sure 
> that over_gpio0 and overo_gpio170 are free. the are not used at all inside 
> the code.  I connected them to debug led0 and debug_led1 and used echo 1> 
> /sys/class/gpio/gpio0/value after setting the direction but nothing at all, 
> the two debug leds are off.
> 

What version of the e100 image are you using. Can you start by making
sure you are using the latest?

http://code.ettus.com/redmine/ettus/projects/usrpe1xx/wiki/FAQ#How-do-I-create-re-create-E1xx-SD-Card-Images

I think earler images will not have access to gpio0 due to some pinmux
stuff in u-boot. I need to double check 170 pinmuxing also. there should
be some free gpios in the 20's with the current image.

> Another question, what is the difference between gpio0 and gpiochip0 found at 
> /sys/class/gpio  

I think the gpiochip entries represent the various banks of gpios.

Philip

>  
>  
> Regards,
> S. Yassin
> HW Engineer
> DLECS
> 
> 
> ________________________________
>  From: Philip Balister <address@hidden>
> To: Sameh Yassin <address@hidden> 
> Cc: GNURADIO <address@hidden> 
> Sent: Wednesday, May 2, 2012 1:33 PM
> Subject: Re: [Discuss-gnuradio] E100 - Interface between OMAP3 and FPGA
>  
> On 05/01/2012 04:28 AM, Sameh Yassin wrote:
>> Hello Dear ,
>>
>> I used the first link to use overo GPIOs on the E100 to communicate with the 
>> SPARTN3AN FPGA. 
>>
>> I'm  doing the following:
>> 1- I chose an empty GPIO input to the FPGA (for example overo_gpio22).
>> 2- I modified the FPGA image so that debug_led1 = over_gpio220
>> 3- I'll set and clear overo GPIO using the bash shell as I read in the first 
>> link that u recommended.
>>
>> The problem:
>>   Although the following gpios are free on the FPGA. There are other gpios  
>> valid on the overo. Srictly speaking
>>
>> The free GPIOs on the overo 
>> $ address@hidden:/sys/class/gpio# ls
>>
>> exportgpio16 gpio168    gpiochip128  gpiochip192  gpiochip64  unexport
>> gpio15gpio164  gpiochip0  gpiochip160  gpiochip32   gpiochip96
> 
> It looks like you are running an older version of uhd, which suggests an
> older kernel version. The older driver claimed a few extra gpio's for
> testing purposes.
> 
> I see:
> 
> address@hidden:~# ls /sys/class/gpio/
> export    gpio16@   gpio173@    gpiochip128@  gpiochip32@  unexport
> gpio114@  gpio164@  gpio175@    gpiochip160@  gpiochip64@
> gpio15@   gpio168@  gpiochip0@  gpiochip192@  gpiochip96@
> 
> Note the extra gpio's exposed to user space. These are used by uhd for
> signaling and configuring the clock generator.
> 
> Philip
> 
>>
>>
>> The free gpios at the FPGA found at u1e.v
>> input overo_gpio0, input overo_gpio14, input overo_gpio21, input 
>> overo_gpio22,  // Misc GPIO
>>
>> input overo_gpio23, input overo_gpio64, input overo_gpio127, // Misc GPIO
>> input overo_gpio176, input overo_gpio163, input overo_gpio170, // Misc GPIO
>>
>> Is that normal of I did something wrong at the kernel at the overo?
>>
>> Regards,
>> S. Yassin
>> HW Engineer
>> DLECS
>>
>>
>> ________________________________
>>   From: Philip Balister <address@hidden>
>> To: Sameh Yassin <address@hidden> 
>> Cc: "address@hidden" <address@hidden> 
>> Sent: Saturday, April 28, 2012 2:18 PM
>> Subject: Re: [Discuss-gnuradio] E100 - Interface between OMAP3 and FPGA
>>   
>> On 04/28/2012 08:07 AM, Sameh Yassin wrote:
>>> Dear all,
>>>
>>> I need to send data from the OMAP3 to the Spartan3an FPGA. As I understand 
>>> ,from the wiki and presentations,  there are two ways to communicate 
>>> namely; using setting_reg and GPIO.  The second way seems easier so I'll 
>>> try it first. 
>>>
>>> I intend to set or clear the free GPIOS on the Spartan FPGA such as 
>>> over_gpio_22. I  added the following code to the example tx_waveforms.cpp. 
>>>
>>>           static struct gpio gpio_test = { 22, GPIOF_OUT_INIT_LOW, 
>>> "OVERO_GPIO_22" };
>>> gpio_set_value(22,1);
>>> //set gpio22 which is connected to pin IO_L30N_0
>>>
>>>
>>> I tried to compile then I got the error that can't find GPIO.h. 
>>>
>>> My question: did I use the correct high level function or I used a "lower 
>>> level" that is used to implement the function? 
>>
>> This is the easiest way to toggle gpio's from userspace.
>>
>> http://wiki.gumstix.org/index.php?title=GPIO#Accessing_GPIO.27s_from_userland
>>
>> Also:
>>
>> http://elinux.org/GPIO
>>
>> The kernel on the e100 already supports the sysfs entries for gpio's.
>> (UHD uses it)
>>
>> Philip
>>
>>>   
>>>
>>>   
>>> Regards,
>>> S. Yassin
>>>
>>>
>>>
>>> _______________________________________________
>>> Discuss-gnuradio mailing list
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