TMS320F28335: SM320F28335

Navin,

We will need to either enable JTAG Wait In Reset or select an unused comm boot mode.  From your description it sounds like the device may have accidentally programmed the CSM passwords and will not connect due to the CSM being active.

Placing the device in either of the above states will prevent it from executing code in Flash, which is secure.

This can happen if the program operation is interrupted before it completes, not sure if you recall if there was a power interruption or external reset during this time.

At any rate, once you connect, please look at the CSM password locations at the end of Sector A flash(last 8 words).  If you can read all 0xFFFF, then we aren't locked.  If you read all 0x0000, then the device is locked and we will need to replace the device.

Best,

Matthew

Hi,

Thanks for support, I am working with Navin and having few doubts wanted to ask you. Please refer my comments below in italic format.

We will need to either enable JTAG Wait In Reset or select an unused comm boot mode.

how to enable JTAG wait in reset of debugger? will this help to connect debugger to read / connect controller state.

From your description it sounds like the device may have accidentally programmed the CSM passwords and will not connect due to the CSM being active.

it was working fine & we did not flash any program, our CSM password is by default set to 0xffff and also reading at power up.

This can happen if the program operation is interrupted before it completes, not sure if you recall if there was a power interruption or external reset during this time.

we did not flash any program and it was working fine but after some time it is not working now

At any rate, once you connect, please look at the CSM password locations at the end of Sector A flash(last 8 words).  If you can read all 0xFFFF, then we aren't locked.  If you read all 0x0000, then the device is locked and we will need to replace the device

we are not able to connect debugger to controller and giving error like above mentioned so please let us know if there is any way to read flash sector A location, is there any way to know controller is powering up by monitoring some pins like reset or any other pin to know controller is damaged or not.

Thanks for valuable inputs again!

Prashant,

You can monitor XRSn pin, and see if it is stable or there is a period pulse low.  This would indicate the device WD is timing out, but would tell us the device is alive.

Let's try the check boot pins mode shown in the image below.  This will ensure the device doesn't run from secure memory when you are trying to connect.  If the connection doesn't work with this enabled at power up, then you likely have a different issue than the CSM.

Do you have another JTAG pod you could try to see if that is the issue?

Best,

Matthew

Hi,

Thanks for reply.

we measured XRSn pin status on scope please refer below image. the pin remains high after this and we have turned off watchdog internal also external

and we have also monitored the boot mode pins and below is the status.

SYSCLOCKOUT can be measured ? to check controller is working or not 

SYSCLKOUT should be active on this device from reset, so you can see the clock rate of the device.  Let me know what you see on the pin.

In terms of XRSn and the boot pins, XRSn is inactive so as you said the watchdog isn't triggering which would indicate your code is running and disabled it.

I'm not sure why you can't connect to the device, can you try the Boot Mode 3 setting I highlighted in my last post to see if this changes anything?

Do you have another F28335 MCU you can try to see if the emulator is still OK?

Best,
Matthew

Hi Matthew,

Initially we measured XCLKOUT pin, and there was no output. Then we checked for Oscillator, we found t]out that oscillator was not working properly. We removed the oscillator, and somehow we gave 27MHz to Clock input of microcontroller pin. It started working fine.

We are still not sure how the oscillator got bad. We are using ASEMPC-27.000MHZ-Z-T this part in our design.

Thanks for your support 

Regards

Navin Singh