TMDSCNCD28P65X: DCL_runPI_L1 parameters

Andrew Andoh

Tool/software:

Hi,

I am having trouble figuring out the limits parameters in DCL_runPI_L1. Does it have both the integrator limit (Imax, Imin) and control limit(Umax,Umin) in the .asm? I cannot tell explicitly.

I need the integrator flag most importantly for my application; The lk flag equivalent in TI PID sample codes.

Thank you in advance.

11 months ago

0 Sen Wang 11 months ago

TI__Intellectual 2326 points

Hello,

DCL_runPI_L1 is the CLA version of DCL_runPI_C1/C2 (serial PI) and it does not have an integrator limit, only a saturation clamp.

The only PI controller that uses an integrator limit is DCL_runPI_C5. Which is C-source of parallel PI w/ enhanced anti-windup. And unfortauntely we don't have a C28 assmembly nor CLA version of the code.

But since CLA takes in C-syntax code. We could easily adapt C5 into CLA. The only difference is that anything regarding CSS and SPS struct needs to be removed. I.e:

// CLA source code of DCL_runPI_C5 -> parallel pi with enhanced anti-windup
static inline float32_t DCL_runPI_L6(DCL_PI_CLA *p, float32_t rk, float32_t yk)
{
    float32_t v1, v5, v7, v8;
    uint16_t l11, l12, l14, l17, l18, l19;
    
    asm(" MSETFLG   RNDF32=1");
    v1 = rk - yk;
    v5 = (v1 * p->Ki * p->i6) + p->i10;
    p->i10 = v5;
    v7 = (v1 * p->Kp) + v5;
    v8 = (v7 > p->Umax) ? p->Umax : v7;
    v8 = (v8 < p->Umin) ? p->Umin : v8;
    l17 = ((v7 - v8) == 0) ? 1U : 0U;
    l11 = (v5 >= p->Imax) ? 1U : 0U;
    l12 = (v5 <= p->Imin) ? 1U : 0U;
    l19 = (v5 > 0) ? 1U : 0U;
    l14 = (v1 > 0) ? 1U : 0U;
    l18 = l17 & (!(l11 | l12) | (l19 ^ l14));
    p->i6 = (l18 == 0U) ? 0.0f : 1.0f;


    return(v8);
}

Alternatively, you can also just use serial/parallel PID controllers that's already written in assembly for CLA (DCL_runPID_L1 & L2).

Please let me know if you have any addintional questions.

Best,

Sen Wang

0 Andrew Andoh 11 months ago in reply to Sen Wang

Prodigy 50 points

Understood. How many cycles would DCL_runPI_L6 take? An estimate is also fine in this case.

Andrew.

+1 Sen Wang 11 months ago in reply to Andrew Andoh

TI__Intellectual 2326 points

Hi Andrew,

I can provide a rough estimate based on existing benchmarks from the DCL user's guide:

Judging by how DCL_runPI_C6 and DCL_runPI_L5 are roughly similar (PI w/ tustin integrator in C28 C-source vs CLA C-source). The CLA C-source variant of C5 benchmark will be similar to DCl_runPI_C5 (~190 cycles).

In contrast, the assembly variant of CLA implementations are much faster, DCL_runPID_L1/L2 are 53 & 45 cycles. And the regular L1/L2 PIs are 34 & 33 cycles.

Therefore, I would recommend to just use PID controller instead in CLA, if performance is a concern. (serial/parallel: DCL_runPID_L1/L2).

Best,

Sen Wang

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMDSCNCD28P65X: DCL_runPI_L1 parameters