PRU_EVTOUT_1 sent from PRU0 does not clear with sysevent = PRU0_ARM_INTERRUPT

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1

Hello all!

I have been working on a code where in which I use the interrupt PRU_EVTOUT_1 as a heartbeat from the PRU to the host. Currently, however, I have not been able to clear the interrupt so that it can be sent again. A (partial) minimal example is found below. As it is, the code does not work (for me at least… maybe I’m doing something stupid). This code works when PRU_EVTOUT_1 is replaced by PRU_EVTOUT_0 or when PRU0_ARM_INTERRUPT is replaced by PRU1_ARM_INTERRUPT.

I edited prussdrv.c to find out where the issue is coming from and it seems that the wrong bit is cleared in SECR1 using the values below. That is:

  • when I send PRU0_R31_VEC_VALID | PRU_EVTOUT_0, I get SERC1 = 0x80000, which is correctly cleared by PRU0_ARM_INTERRUPT = 19
  • when I send PRU0_R31_VEC_VALID | PRU_EVTOUT_1, I get SERC1 = 0x100000, which is correctly cleared by PRU1_ARM_INTERRUPT = 20

That makes sense given that PRU0_R31_VEC_VALID | PRU_EVTOUT_1 = ``PRU1_ARM_INTERRUPT + 16. The second form is found in the example codes for prussdrv, whereas the first one is used in Derek Molloy’s EBB (ultrasonic example, chapter 13).

Is PRU_EVTOUT_1 from PRU0 the same as sending PRU_EVTOUT_0 from PRU1? That seems odd, but I wasn’t able to figure it out from the reference guide. I must be doing something wrong, I just don’t know what!

Any help is appreciated! I am using the latest version of the am335x_pru_package (built directly from the repository).

Cheers!

prumain.p:

`
.origin 0 // start of program in PRU memory
.entrypoint START // program entry point

#define PRU0_R31_VEC_VALID 32
#define PRU_EVTOUT_0 3
#define PRU_EVTOUT_1 4

START:
// Send interrupt to host
MOV R31.b0, PRU0_R31_VEC_VALID | PRU_EVTOUT_1

// Wait for 1 second
MOV r3, DELAY_MS
DELAY:
SUB r3, r3, 1
QBNE DELAY, r3, 0

// Send interrupt to host
MOV R31.b0, PRU0_R31_VEC_VALID | PRU_EVTOUT_1

// Halt
HALT

`

main.c:

`
/* Wait for PRU_EVTOUT_1 */
n = prussdrv_pru_wait_event(PRU_EVTOUT_1);
printf(“This is the PRU_EVTOUT_1 number %d.\n”, n);
prussdrv_pru_clear_event(PRU_EVTOUT_1, PRU0_ARM_INTERRUPT);

/* Wait for PRU_EVTOUT_0 (will go through this one instead of waiting for the delay in prumain.p */
n = prussdrv_pru_wait_event(PRU_EVTOUT_1);
printf(“This is the PRU_EVTOUT_1 number %d.\n”, n);
prussdrv_pru_clear_event(PRU_EVTOUT_1, PRU0_ARM_INTERRUPT);

`

2

<luizchamon@...> writes:

Hello all!I have been working on a code where in which I use the interrupt

PRU_EVTOUT_1 as a heartbeat from the PRU to the host. Currently, however, I
have not been able to clear the interrupt so that it can be sent again. A
(partial) minimal example is found below. As it is, the code does not work
(for me at least... maybe I'm doing something stupid). This code works when
PRU_EVTOUT_1 is replaced by PRU_EVTOUT_0 or when PRU0_ARM_INTERRUPT is
replaced by PRU1_ARM_INTERRUPT.I edited prussdrv.c to find out where the
issue is coming from and it seems that the wrong bit is cleared in SECR1
using the values below. That is:- when I send PRU0_R31_VEC_VALID |
PRU_EVTOUT_0, I get SERC1 = 0x80000, which is correctly cleared by
PRU0_ARM_INTERRUPT = 19- when I send PRU0_R31_VEC_VALID | PRU_EVTOUT_1, I
get SERC1 = 0x100000, which is correctly cleared by PRU1_ARM_INTERRUPT =
20That makes sense given that PRU0_R31_VEC_VALID | PRU_EVTOUT_1 =
PRU1_ARM_INTERRUPT + 16. The second form is found in the example codes for
prussdrv, whereas the first one is used in Derek Molloy's EBB (ultrasonic
example, chapter 13).Is PRU_EVTOUT_1 from PRU0 the same as sending
PRU_EVTOUT_0 from PRU1? That seems odd, but I wasn't able to figure it out
from the reference guide. I must be doing something wrong, I just don't know
what!Any help is appreciated! I am using the latest version of the
am335x_pru_package (built directly from the repository).Cheers!prumain.p:

.origin 0 // start of program in PRU

memory.entrypoint START // program entry point#define
PRU0_R31_VEC_VALID 32#define PRU_EVTOUT_0 3#define PRU_EVTOUT_1 4START:
// Send interrupt to host MOV R31.b0, PRU0_R31_VEC_VALID | PRU_EVTOUT_1
// Wait for 1 second MOV r3, DELAY_MS DELAY: SUB r3, r3, 1
QBNE DELAY, r3, 0 // Send interrupt to host MOV R31.b0,
PRU0_R31_VEC_VALID | PRU_EVTOUT_1 // Halt HALT

main.c:
/* Wait for PRU_EVTOUT_1 */n =

prussdrv_pru_wait_event(PRU_EVTOUT_1);printf("This is the PRU_EVTOUT_1
number %d.\n", n);prussdrv_pru_clear_event(PRU_EVTOUT_1,
PRU0_ARM_INTERRUPT);/* Wait for PRU_EVTOUT_0 (will go through this one
instead of waiting for the delay in prumain.p */n =
prussdrv_pru_wait_event(PRU_EVTOUT_1);printf("This is the PRU_EVTOUT_1
number %d.\n", n);prussdrv_pru_clear_event(PRU_EVTOUT_1,
PRU0_ARM_INTERRUPT);