RTEMS on Beaglebone Black
newsgroups at smartcontroller.com.au
Tue Jul 28 07:23:01 UTC 2015
BTW I changed above code for 4 interrupts
On Tue, Jul 28, 2015 at 5:19 PM, Angelo Fraietta <
newsgroups at smartcontroller.com.au> wrote:
> I can confirm that the interrupts do work, however, it is on both edges,
> not just the rising.
> I wanted to see what sort of performance I could get out of the interrupts
> by inputting various frequency signals
> I modified the code so 13 would toggle every 8 interrupts. It toggled
> after four full pulses, therefore it interrupted on both edges (see code at
> Also, I found that it took 1.3us to service the interrupt (I measured the
> time between the edge of interrupt pin and the toggle point of 13). The
> beagle is supposed to be 1 1GHz machine. Is there any way I can push faster
> than 1.3us with a setting in RTEMS (eg nanoseconds per tick) or is 1.3us my
> absolute best?
> rtems_isr GPIO1_IRQHandler (rtems_vector_number vector)
> static int i = 0;
> //Toggle other three LEDs here:
> *(unsigned long *)(GPIO1_ADDR+GPIO_DATAOUT) ^= ((1<<22)| (1<<23)
> //Clear interrupt:
> //Per AM335x technical reference manual, we can read IRQSTATUS,
> // and then write corresponding bits on IRQSTATUS to clear whichever one
> was serviced.
> // in this application it's hard coded to number 12 so I just write that
> // For some reason writing IRQSTATUS value back to itself doesn't clear
> the interrupt.
> unsigned long irqstat = *(unsigned long*)(GPIO1_ADDR + GPIO_IRQSTATUS_1);
> *(unsigned long*)(GPIO1_ADDR + GPIO_IRQSTATUS_1) = (1<<12);
> // we will toggle every
> //*(unsigned long*)(GPIO1_ADDR + GPIO_IRQSTATUS_1) = irqstat;
> if (!(i % 4))
> *(unsigned long *)(GPIO1_ADDR+GPIO_DATAOUT) ^= (1<<13);
> On Tue, Jul 28, 2015 at 1:54 AM, Steve B <sbattazzo at gmail.com> wrote:
>> Hi Angelo,
>> Here's a handy diagram that shows which ones are which (found on Google
>> GPIO1_12 is connector P8 pin 12. I think I used the adjacent pin (P8 pin
>> 11, or GPIO1_13) and installed a jumper wire between the two.
>> I think it says so in my comments too but I know that may not exactly
>> jump out.
>> On Sun, Jul 26, 2015 at 6:38 PM, Angelo Fraietta <
>> newsgroups at smartcontroller.com.au> wrote:
>>> Greetings Steve, I have modified your code so the standard task only
>>> toggles one LED and the interrupt on GPIO12 should toggle the other 3.
>>> However, IO cannot for the life of me find which pin is GPIO12 so I can
>>> test on the hardware. I have posted the code with the mods I made at the
>>> bottom of this email
>>> What physical pin should I be toggling to make it work?
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