TMS320F28P650DK: Same MotorControl SDK code works on CPU1 but not on CPU2 – TMS320F28P650DK6

Part Number: TMS320F28P650DK

Hello TI Team,

I am working on a dual-CPU application using the TMS320F28P650DK6 MCU and the TI C2000 MotorControl SDK.

I have a MotorControl SDK application that runs correctly when executed on CPU1, but the same application does not behave correctly when executed on CPU2.

MCU / Software

• MCU: TMS320F28P650DK6

• Software: TI C2000 MotorControl SDK

• IDE: Code Composer Studio

• CPU1 + CPU2 dual-core application

• Motor-control application using ePWM, ADC, and control ISR

• Both CPUs are configured with the required peripheral clocks.

What I have observed

The same motor-control code works correctly on CPU1.

When I move/run the same control application on CPU2, the motor-control behavior is different.

For example, at approximately 20 Hz speed reference:

Therefore, the CPU2 application is executing, but the motor-control feedback/control behavior is not equivalent to CPU1.

CPU1 / CPU2 clock observation

I compared the CPU1 and CPU2 device.h and device.c configurations.

Both CPUs are configured for:

• 20 MHz XTAL

• 200 MHz SYSCLK

• 50 MHz LSPCLK

The CPU1 code boots CPU2 using Device_bootCPU2().

I also tested a simple LED toggle on both CPUs.

The LEDs do not turn ON/OFF at exactly the same instant, but the time offset remains approximately constant for every cycle.

Therefore, I believe this is primarily a startup/phase offset rather than a continuously accumulating CPU clock-frequency difference.

Peripheral configuration

I have enabled/configured the peripherals required by the CPU2 application, including the peripherals used by the MotorControl SDK application.

The Device_enableAllPeripherals() implementation is also present on CPU2.

I have therefore not intentionally left the required ePWM/ADC/peripheral clock disabled on CPU2.

CPU2 boot sequence

CPU1 releases CPU2 from reset using:

void Device_bootCPU2(uint32_t bootmode)
{
    IPC_setBootMode(IPC_CPU1_L_CPU2_R,
                    (BOOT_KEY | bootmode));

    IPC_setFlagLtoR(IPC_CPU1_L_CPU2_R, IPC_FLAG0);

    SysCtl_controlCPU2Reset(SYSCTL_CORE_DEACTIVE);

    while(SysCtl_isCPU2Reset() == 0x1U);
}

CPU2 successfully starts executing code, so CPU2 is not simply remaining in reset.

My main question

What are the CPU1-specific dependencies in the TI C2000 MotorControl SDK that could cause the same motor-control application to work on CPU1 but behave differently when executed on CPU2?

In particular, could you please advise what I should check regarding:

1. ePWM ownership between CPU1 and CPU2

2. ADC ownership/configuration

3. ePWM → ADC SOC synchronization

4. CPU2 interrupt configuration and vector table

5. Motor-control ISR execution rate

6. CPU timer / system clock dependencies

7. CLA or other accelerator dependencies

8. Shared RAM / MSGRAM / IPC configuration

9. Peripheral access or ownership restrictions between CPU1 and CPU2

10. Any MotorControl SDK modules that assume execution on CPU1

11. Any CPU1-specific initialization required before the MotorControl SDK can run on CPU2

12. Whether ePWM time-base synchronization needs to be explicitly configured between CPU1 and CPU2

Additional question about CPU synchronization

Since CPU2 is released from reset by CPU1, should I expect a fixed phase offset between CPU1 and CPU2 execution?

If so, is there any recommended TI mechanism for synchronizing the motor-control timing/ISR between CPU1 and CPU2, rather than simply synchronizing the software startup?

I can provide the complete CPU1 and CPU2 project files, linker command files, device.c/.h, ePWM/ADC configuration, and MotorControl SDK source if required.

I would particularly appreciate guidance on how to identify why the MotorControl SDK control loop produces correct speed feedback on CPU1 but almost zero speed feedback on CPU2.

Thank you.