Hi everyone, I started using IEP timer a few days ago and I faced with one
problem which could not be solved up to now.
There are parts of my code C and code assembly for PRU.
The C code:
while(1)
{
char filename[100];
strcpy(filename, "frame_");
sprintf(filename,"%d",number);
cout << "Capture" << filename << endl;
prussdrv_pru_wait_event (PRU_EVTOUT_1);
prussdrv_pru_clear_event (PRU1_ARM_INTERRUPT);
number++;
}
And the assembly code for PRU
#include "PRU_memAccess_DDR_PRUsharedRAM.hp"
#define CONST_IEP C26
MEMACCESS_DDR_PRUSHAREDRAM:
// Enable OCP master port
LBCO r0, CONST_PRUCFG, 4, 4
CLR r0, r0, 4 // Clear SYSCFG[STANDBY_INIT] to enable OCP
master port
SBCO r0, CONST_PRUCFG, 4, 4
// *************************************
// * Timer Configuration *
// *************************************
// spruhf8 AM335x PRU-ICSS Reference Guide 10.x
LBCO r6, CONST_IEP, 0x40, 40 // Read all 10 32-bit
CMP registers into r6-r15
OR r6, r6, 0x03 // Set count reset and
enable compare 0 event
// Set loop period to 1S
MOV r8, 1000000000
SBCO r6, CONST_IEP, 0x40, 40 // Save 10 32-bit CMP
registers
MOV r2, 0x00000551 // Enable counter,
configured to count nS
(increments by 5 each clock)
SBCO r2, CONST_IEP, 0x00, 4 // Save IEP GLOBAL_CFG
register
// *************************************
// * Waiting for timer *
// *************************************
WAIT:
LBCO r2, CONST_IEP, 0x44, 4 // Load CMP_STATUS register
QBBC WAIT, r2, 0 // Wait until counter times out
SBCO r2, CONST_IEP, 0x44, 4 // Clear counter timeout bit
// Send notification to Host for program completion
MOV r31.b0, PRU1_ARM_INTERRUPT+16
JMP WAIT
// Halt the processor
HALT
The function of this program is to display (Capture+"number") on the screen
after 1s. The number is increasing. When I ran this code, the result was:
Capture 0 (delay) Capture 1 Capture 2 (delay) Capture 3 Capture 4 (delay)
... It means the number is increase by 2 each 1s (I want it to increase by
1).
I have tried many different ways but I could not find the solution. I
thought that the instruction prussdrv_pru_clear_event (PRU1_ARM_INTERRUPT); in
code C need a period of time to clear the interrupt. I tested this idea by
adding 1 more prussdrv_pru_wait_event (PRU_EVTOUT_1); after this. The code
was changed to:
while(1)
{
char filename[100];
strcpy(filename, "frame_");
sprintf(filename,"%d",number);
cout << "Capture" << filename << endl;
prussdrv_pru_wait_event (PRU_EVTOUT_1);
prussdrv_pru_clear_event (PRU1_ARM_INTERRUPT);
prussdrv_pru_wait_event (PRU_EVTOUT_1); //Additional
instruction
number++;
}
Fotunately, the problem is solved. I don't know how to explain for this. I
think that PRU sends another interrupt to main processor when the timer is
matched. Can anyone help me to explain this?
Best regards,
Phong
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