CCS: DSS: Unable to access DEMCR register

Shantanu Sampath63

Other Parts Discussed in Thread: MSP432E401Y

Tool/software: Code Composer Studio

I would like to measure clock cycles between any two breakpoints in the code. For this, I am using the ARM DWT registers to read the clock count. I am trying to perform the following R/W operations using Javascript:

// enable the use DWT
*DEMCR = *DEMCR | 0x01000000;

// Reset cycle counter
*DWT_CYCCNT = 0;

// enable cycle counter
*DWT_CONTROL = *DWT_CONTROL | 1 ;

I am unable to write to the DEMCR register using writeRegister, writeWord and writeData APIs. Please help.

over 7 years ago

0 Shantanu Sampath63 over 7 years ago

Prodigy 190 points

Follow up:
writeData() and writeWord throw error 0x20000 while attempting to write to any of the ARM register.

I would also like to know if there is a way to programmatically implement the EVENT COUNT feature of CCS, using DSS.

0 Ki over 7 years ago in reply to Shantanu Sampath63

TI__Guru**** 472291 points

Hello,
What exact device are you using?

Thanks
ki

0 Shantanu Sampath63 over 7 years ago in reply to Ki

Prodigy 190 points

MSP432E401Y

0 Ki over 7 years ago

TI__Guru**** 472291 points

Shantanu Sampath63 said:
I am unable to write to the DEMCR register using writeRegister, writeWord and writeData APIs. Please help.

Fore memory mapped registers, you need to see if the register is associated with a group in the Register view. If it is, you need to prepend the group name followed by an underscore. For example, I see DEMCR is part of the COREDEBUG group in the Register view. So I would access it via:

debugSession.memory.writeRegister("COREDEBUG_DEMCR", 0);

Thanks

0 Shantanu Sampath63 over 7 years ago in reply to Ki

Prodigy 190 points

It says "Register COREDEBUG_DEMCR not found"

0 Ki over 7 years ago in reply to Shantanu Sampath63

TI__Guru**** 472291 points

Sorry, it appears that for the MSP432E401Y, that register is not defined. I originally tried on an MSP432P401R, and that register is defined under the COREDEBUG group. But on MSP432E401Y, that group does not exist.

0 Ki over 7 years ago in reply to Ki

TI__Guru**** 472291 points

Hi Shantanu,
I tried this out on a MSP432E401Y board. Regarding the register name, it is as I mentioned in my previous post.

However, the memory writeWord APIs by address should work.

This API works fine:

debugSession.memory.writeWord(0, 0xE000EDFC, 0x11000001);

Can you start a debug session, connect to the target and open a scripting console? Then type the below in the scripting console:

activeDS.memory.writeWord(0, 0xE000EDFC, 0x11000001)

let me know if this works for you

Thanks
ki