run an isr on the PWM in Rabbit Core 3000 (LP3500)

Rabbit Rabbit Software
, ,
1

I need to run an isr on the PWM output in an LP3500. I can’t find any example code.
the “rntVal” is coming back as 0 (invalid vector?)
I am using the following lines to set up the isr:


void isr_PWM();   //ISR function for PWM

void main ()
{
   brdInit();
   rtnVal = SetVectIntern(0x170, isr_PWM);    //assigning interrupt vector to ISR function
.
.
.
}

nodebug root interrupt void isr_PWM() {   //ISR function for PWM
   flagPWMrun = 1; 	//use to start an action related to the PWM running
   cntPWMcycles++;	//increment the PWMcycle counter

}
2

Per the documentation for SetVectIntern(), you should be using 0x17 as the first parameter. Give that a try and see if it starts working.

(If you place your edit cursor in or after the word “SetVectIntern” in your code and press CTRL-H, it will pull up function help.)

3

Excellent. That did work to get the vector setup. It is confusing when the “offset” is also given and it is almost the same “0x0170”. But the isr still doesn’t trigger. I guess I need to set bits 1 and 2 of register PWL0R to some non-zero value to give the isr a priority (if those bits are 0 the isr is disabled). What is the best way to do that. It seems that the WrPortI(PWL0R, NULL, 0x02) command should work, but I can’t read back that register and it seems like sometimes the code gets stuck on that command.

4

When ever I set bit 1 in PWL0R to “1” the code will stop working. Is it a problem to set the isr priority to 1?

5

I am using separate instruction and code space. The documentation says I need this command option:
#if SEPARATE_INST_DATA && (_RK_FIXED_VECTORS)
interrupt_vector pwm_intvec isr_PWM;
#else
SetVectIntern(0x17, isr_PWM); // set up ISR
#endif

Problem is I get the following error when I compile:
line 465 : ERROR ServoAxis-TampShuttle-1-2-test6.C : Vector pwm_intvec undefined

Any idea what I can do about it?
Can I define it myself, or do I have to modify libraries?

6

So pwm_intvec should never get used. The Rabbit 3000 rev 0 doesn’t support a PWM interrupt, and the Rabbit 3000 rev 1 doesn’t use fixed interrupt vectors. Are you compiling your program for the proper target of an LP3500, and verified that your LP3500 has a Rabbit 3000 rev 1 chip and therefore supports interrupt vectors?

If you add this line to your program, what does it output?
printf("CPU_ID=0x%x
", CPU_ID);

It should print 0x101 for a Rabbit 3000 rev 1. If it prints 0x100 you have a Rabbit 3000 rev 0 and that doesn’t support PWM interrupts.

Also, please confirm that you’re using Dynamic C 9.62 or 9.62A.