TMS320F28066 running at 90MHz hangs if CSM password enabled. Same code with 80MHZ runs fine.

Bhaskar Reddy

Other Parts Discussed in Thread: TMS320F28066

We are running TMS320F28066 at 90MHz. The code runs fine without CSM password. If the same code is loaded with CSM password the code hangs (looks to be ITRAP).

Same CSM password enabled code, if I just change the frequency to 80 MHz it runs again. I compared the binaries of the two builds 80 and 90MHz. They are exactly same for entire flash range, except the PLL register init constants.

Note that my PLL init is Div by 4 and Mul by 18 for 20MHz external crystal to make 90MHz. Mul by 18 option is newly added to the datasheet when 90MHz support is added.

I could not able to understand why the same code with clock freq different behaving differently.

Is this a known issue or am I missing something.

over 11 years ago

0 Hareesh Janakiraman over 11 years ago

TI__Guru* 95315 points

Bhaskar,

In how many devices have you seen this behavior? If you have seen this in only one device, would it be possible for you to try this in a few boards?

Hareesh

0 Bhaskar Reddy over 11 years ago in reply to Hareesh Janakiraman

Intellectual 980 points

Hi Hareesh,

I didn't suspect it as a device problem because, 80MHz CSM working fine and 90MHz without CSM working fine.

I tried this on only one device. Will try on other board and update you.

Any reason why TI released this chip as 80 MHz devices but later updated as 90MHz device. All the manufactured devices support or is there any date code to differentiate?

0 David M. Alter over 11 years ago in reply to Bhaskar Reddy

TI__Guru 61235 points

Bhaskar,

Bhaskar Reddy said:
Any reason why TI released this chip as 80 MHz devices but later updated as 90MHz device. All the manufactured devices support or is there any date code to differentiate?

The design goal was 80 MHz, and initial pre-production datasheets showed 80 MHz. Characterization tests showed the device worked fine at 90 MHz, so device was released to production at 90 MHz. This is not an unprecedented occurrence. All production (TMS devices) F2806x devices are good for 90 MHz. Early samples (TMX devices) were probably only tested to 80 MHz.

- David

0 Bhaskar Reddy over 11 years ago in reply to Hareesh Janakiraman

Intellectual 980 points

We have tested on two more devices and found that the problem remains same.

0 Bhaskar Reddy over 11 years ago in reply to Bhaskar Reddy

Intellectual 980 points

Anybody successful in using 90MHz with CSM being enabled, please let me know.

0 Jason Whiles over 11 years ago in reply to Bhaskar Reddy

TI__Expert 5450 points

Bhaskar,

Could you post all of your Flash Wait State settings as well?

Thanks,

Jason

0 David M. Alter over 11 years ago in reply to Bhaskar Reddy

TI__Guru 61235 points

Bhaskar Reddy said:
Anybody successful in using 90MHz with CSM being enabled, please let me know.

I just tested at 90 MHz with CSM passwords programmed and CSM locked. No problem. Test was done on F28069 ControlStick. You can try the same code in appnote SPRA958, F28069_nonBIOS_flash example. As is, the passwords are all 0xFFFF. So, change to something else. I just changed one of them to 0xFFFE. Note that you should read the appnote chapter describing the code first. It drives ePWM1 pin and also another GPIO to blink the LED on the board. Make sure it won't cause contention on your board. If so, modify file gpio.c to keep that pin as an input.

- David

0 Bhaskar Reddy over 11 years ago in reply to David M. Alter

Intellectual 980 points

I tried the example project (Control suite on a separate test board. Its working fine.

For testing purpose, I made while loop of LED toggling in my application in the main file itself. Its behaving differently with and without password. Blink rate is slower with password, compared to without password.

I removed all c files in the project and tried again. This time the LED blink pattern is same for both with and without password case.

I'm still investigate in to this.

My flash settings are 3, 3, 5 for wait states.

0 Hareesh Janakiraman over 11 years ago in reply to Bhaskar Reddy

TI__Guru* 95315 points

Bhaskar,

We have tried this with 3 different test cases, but have not been able to reproduce the problem. Could you please update us on where your investigation stands?

Hareesh

0 Hareesh Janakiraman over 11 years ago in reply to Hareesh Janakiraman

TI__Guru* 95315 points

Bhaskar,

Please respond.

Regards,

Hareesh

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TMS320F28066 running at 90MHz hangs if CSM password enabled. Same code with 80MHZ runs fine.