Debug Connection Error in ARM development studio

Hi

My name is Stephen and I work at Arm.

Are you sure that your program starts and completes correctly?  To check, I suggest you place breakpoints at __main, main() and on the final "return 0", then run to each breakpoint in turn.  When compiling/debugging, use a low optimization level (e.g. -O0) as a starting point.

On reset, Arm processors in general need to execute some startup code to setup the Stack Pointer, vector table, MPU, etc.  Do you have any startup code?

Please take a look at the ready-made Examples that are provided in Arm DS.  There is an example for Cortex-M7 named "startup_Cortex-M7_AC6".  This starts a timer by writing to a volatile memory-mapped register, in a similar way to what you are trying now.

You can import the examples into your workspace as follows:

1. Select File > Import... to open the Import Selection dialog
2. Expand the Arm Development Studio group and select Examples and Programming Libraries [Next]
3. Expand the Examples group to view the example categories
4. Either select one (or more) of the example categories to import, or expand the example categories to view/select individual examples in each category.  You can also search for e.g. "startup_Cortex-M7_AC6".
5. Click Finish to import the selected examples into your workspace.

Hope this helps

Stephen

Hi

My name is Stephen and I work at Arm.

Are you sure that your program starts and completes correctly?  To check, I suggest you place breakpoints at __main, main() and on the final "return 0", then run to each breakpoint in turn.  When compiling/debugging, use a low optimization level (e.g. -O0) as a starting point.

On reset, Arm processors in general need to execute some startup code to setup the Stack Pointer, vector table, MPU, etc.  Do you have any startup code?

Please take a look at the ready-made Examples that are provided in Arm DS.  There is an example for Cortex-M7 named "startup_Cortex-M7_AC6".  This starts a timer by writing to a volatile memory-mapped register, in a similar way to what you are trying now.

You can import the examples into your workspace as follows:

1. Select File > Import... to open the Import Selection dialog
2. Expand the Arm Development Studio group and select Examples and Programming Libraries [Next]
3. Expand the Examples group to view the example categories
4. Either select one (or more) of the example categories to import, or expand the example categories to view/select individual examples in each category.  You can also search for e.g. "startup_Cortex-M7_AC6".
5. Click Finish to import the selected examples into your workspace.

Hope this helps

Stephen

Hi Stephen 
We are working on a custom built bare-metal ARM Cortex M7 processor.
These examples are beneficial but they are not tailored to our design specifications.
Can you tell us what is the difference between SMM-M7 and SMM-M7CS in Arm/Cortex-M Prototyping System (MPS2)/ ?

To repeat my colleagues comments... are you sure that your code is reaching main()?

A common issue is if you compile your code with FP support, but you have not enabled the FP hardware (which you must do manually in your initialization code).

This results in a fault in the _fp_init() function (part of the C library init code). Try compiling your code explicitly without FP.

Apologies, I should correct my earlier reply.

CS refers to the presence of CoreSight SoC-400 in that design.

https://developer.arm.com/Processors/CoreSight%20SoC-400

See section 8 of AN399:

https://developer.arm.com/documentation/dai0399

Thank you Ronan for all good information provided!

I followed the steps and I can read/write to ITCM and DTCM.
There is only one issue left I assume, which is the shared memory between the CPU and other IPs with the address 0x60000000.
When I want to read/write to this memory, I get this error:

Here is memory information;

Hi again

There are various reasons why the debugger might be unable to read the memory/peripheral at that addresses, for example:

* the peripheral might be powered-down

* the peripheral might need to be explicitly enabled before use

* the MPU might be blocking access to that address

* the memory/peripheral might be inaccessible/disabled for the current processor mode or security state (e.g. some memory/peripherals are only accessible in secure state)

* the memory/peripheral might require a certain access width, e.g. 8-, 16- or 32-bit access.
For example, to read a word with a 16-bit (LDRH) access, you can use:
x /w <width=16>:0x60000000

You'll need to check the specification for your target to investigate what might be preventing the access.

Stephen

Hi Stephen

We realized it was the problem that you mentioned (peripheral might need to be explicitly enabled before use), and the issue is solved now.
Thank you and Ronan for your kind cooperation.

Thanks for letting us know.
If you could mark this thread as Answer Accepted, that'd be appreciated.
Hope your product development now continues smoothly.

Stephen

Thank you Stephen and Ronan;
I already did that for all the conversation.

Just two thing that I really appreciate to know.

1. Is there a command to see the clock speed of my CPU. Since this CPU is not commercialized, I could see small adjustments in the design. I wanted to make sure what the highest clock is.

2. I want to investigate about the memory as well, I want to know the size of ICTM and DTCM, and if there is any other memory designed for the CPU. 

Than you in advance for your kind cooperation.

Hi again,

Sorry, the debugger is not able to show you the clock speed of your CPU.  You'll need to ask your hardware designers for that information.  But you can set the JTAG clock from within the debugger.

The ITCM and DTCM sizes can be read from the CM7_ITCMCR and CM7_DTCMCR.  See:

developer.arm.com/.../instruction-and-data-tightly-coupled-memory-control-registers

The debugger is not able to work out for itself what other memory might be in your system, though you might be able to probe for working memory using the Memory view.  But again, best to ask your hardware designers for that information.  

Hope this helps

Stephen

Hello!
Thanks again.
Appreciate your kind cooperation.

Hi again!
When we used malloc of size 2**15 in C code, it does not allocate.

uint16_t *out = (uint16_t *)malloc(samples_size * sizeof(uint16_t));
if (!out) {
fprintf(stderr, "Memory allocation for out failed.\n");
exit(1);
}
unsigned int samples_size       = 1 << 15;

Our DTCM 256kb and also ITCM is 256kb.

CM7_DTCMCR
x 0xE000EF94
0xE000EF94: 0x00000049

CM7_ITCMCR
x 0xE000EF90
0xE000EF90: 0x00000049

It seems that I cannot use all 256kb that I have in DTCM.
Can you give me insights through this?

Please create a new thread for a new question so others in the community can assist (as well as find answers).

Malloc() will use the heap to allocate memory. Where have you located this (via scatterloading region ARM_LIB_(STACK)HEAP)?

Thank you for your answer, I could not find any documentation regarding this issue, but I created a new thread here:
Memory allocation Issue

It would be appreciated if you help me there.

Warm regards

Mehran