TMS570LC4357: What is the function of the "ERR ENA"-bit of the DCC Module

Max Wittekind

Part Number: TMS570LC4357
Other Parts Discussed in Thread: HALCOGEN

Hi experts,

While configuring the DCC-Modules, we were wondering what the function of the ERR ENA-bit of the DCCGCTRL register (section 15.4.1 TeChnical Reference) is.
As far we understand any error occuring during DCC operation is signaled to ESM. In ESM we can then configure the interrupt generation. We noticed, that forcing an error,
when testing the DCC, always throws an ESM-error whether ERR ENA is configured or not.

(Q1) So what does ERR ENA do?

Thank you and best regards,
Max

over 2 years ago

0 jagadish gundavarapu over 2 years ago

TI__Guru 69891 points

Hi Max,

You are right according to below thread as well.

(+) RM44L920: DCC working verification and no notification. - Arm-based microcontrollers forum - Arm-based microcontrollers - TI E2E support forums

The ERR ENA-bit should control the ESM DCC error. Don't know why it gets failed in your testing.

Let me test the same at my end. If possible, share your code.

Thanks & Regards,
Jagadish.

0 Max Wittekind over 2 years ago in reply to jagadish gundavarapu

Expert 1875 points

Hi Jagadish,

Unfortunately I can not share my code. But I can describe the testing method we are using.
We basically do the following.

1. Configure the DCC clk sources
2. Set the counters in a way that will force a mismatch
3. Start DCC in continuos mode
4. Poll ESM for some time to check if ESM Error gets triggered
5. The moment we detect ESM Error reconfigure DCC counters so that DCC functions correctly
6. delete ESM error and reset nERROR

The following ESM configuration is used:
ESM Group 1 interrupts are turned OFF in ESM
ESM Group 1 triggers nERROR

The following DCC configuration is used:
DCC is Continuos Mode
DCC is enabled

The state of the ERR ENA bit does not seem to matter in this configuration.

Thank you and best regards,
Max

0 jagadish gundavarapu over 2 years ago in reply to Max Wittekind

TI__Guru 69891 points

Hi Max,

Thaks for sharing testing procedure, i will recreate the issue at my end and will update you on monday.

Thanks & Regards,
Jagadish.

+1 jagadish gundavarapu over 2 years ago in reply to jagadish gundavarapu

TI__Guru 69891 points

Hi Max,

Just now i tested on TMS570LC4357 launchpad and observed that the ERR ENA bit working correctly.

This is the result of before set the ERR_ENA bit.

This is the result of after set the ERR_ENA bit.

In conclusion you can clearly see that, DCC1 - error (i.e., Group-1 Channel-30) in ESM register got set only after we did enable the ERR_ENA bit.

The code i tested is a frequency measurement code in HALCoGen examples, i am attaching my code for your reference, please go through it.

DCC_ESM_ERROR_TEST_LC4357.zip

Thanks & Regards,
Jagadish.

0 Max Wittekind over 2 years ago in reply to jagadish gundavarapu

Expert 1875 points

Hi Jagadish,

thank you for the answer. We har the ERR_ENA bit set in another part of the code as well, so after fixing that issue we now see the correct bahaviour.