TMS320F28035: According to UL certification requirements, how to test the internal crystal oscillator

Jim Chen (SEM)

Part Number: TMS320F28035
Other Parts Discussed in Thread: TMS320F280039, , C2000WARE

Hi experts,

My customer need to finish the UL certification and they need to test the internal crystal oscillator. I know there are two internal oscillator and can we use the oscillator for watchdog to test the other oscillator for system?

We want to keep testing if there is a difference in the frequencies of these two crystals.

Thanks and regards,

Jim

over 2 years ago

0 Hareesh Janakiraman over 2 years ago

TI__Guru* 95315 points

Jim Chen (SEM) said:
My customer need to finish the UL certification and they need to test the internal crystal oscillator.

The internal oscillator is not a crystal oscillator.

Jim Chen (SEM) said:
can we use the oscillator for watchdog to test the other oscillator for system?

Yes, you can do that.

Jim Chen (SEM) said:
We want to keep testing if there is a difference in the frequencies of these two crystals.

Once again, there are no "crystals" inside the device. And there will be a difference in the frequencies of these two oscillators. No two oscillators can oscillate at exactly the same frequency. Every oscillator has a tolerance in the PPM range, so their oscillating frequencies will be slightly different.

0 Jim Chen (SEM) over 2 years ago in reply to Hareesh Janakiraman

TI__Intellectual 2400 points

Hi Hareesh,

Thanks a lot for your reply!

Hareesh Janakiraman said:
Jim Chen (SEM) said:
can we use the oscillator for watchdog to test the other oscillator for system?

Yes, you can do that

Can we use two crystal oscillators to timing and compare the difference in code? We need to test the tolerance between oscillators.

Another question is that we use IEC60730 safety lib to test TMS320F28035, can we use this lib to test TMS320F280039 which is not included in the lib now?

Thanks and regards,

Jim

0 Hareesh Janakiraman over 2 years ago in reply to Jim Chen (SEM)

TI__Guru* 95315 points

Jim Chen (SEM) said:
Can we use two crystal oscillators to timing and compare the difference in code?

Sorry, I don't understand what customer is trying to do here.

Jim Chen (SEM) said:
We need to test the tolerance between oscillators.

I don't understand the objective of this test. As mentioned before, no two oscillators will have exactly the same frequency. There will always be a difference, however minor.

Jim Chen (SEM) said:
Another question is that we use IEC60730 safety lib to test TMS320F28035, can we use this lib to test TMS320F280039 which is not included in the lib now?

I will request a safety expert to answer this.

0 Whitney Dewey over 2 years ago in reply to Hareesh Janakiraman

TI__Guru 53935 points

There is a separate diagnostic lib for the F28003x in C2000Ware (look under libraries/diagnostic/).

Whitney

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28035: According to UL certification requirements, how to test the internal crystal oscillator