C6678: IDLE instruction with Power-down

Ralf Goebel

Other Parts Discussed in Thread: TMS320C6678

Hello,

I'm trying to use the IDLE instruction with Power-down enabled in the PDCCMD register. But the DSP starts getting unstable after placing the code section .text into DDR3 memory. The program crashes and I'm not able to make a JTAG connection to the affected core:

Error connecting to the target:
(Error -1144 @ 0x0)
Device core is hung. The debugger attempted to recover debug control, but was unsuccessful. Power-cycle the board. If error persists, confirm configuration and/or try more reliable JTAG settings (e.g. lower TCLK).
(Emulation package 5.1.641.0)

Are there some known limitations?

I'm also not sure about how to set the lower 16 bits of the PDCCMD register. Is there any description available?

Thanks,
Ralf

over 11 years ago

0 Ganapathi Dhandapani95 over 11 years ago

TI__Mastermind 28085 points

Hi,

The C66x CorePac supports the ability to power down various parts of the C66x CorePac. The power down controller (PDC) of the C66x CorePac can be used to power down L1P, the cache control hardware, the DSP, and the entire C66x CorePac. These power-down features can be used to design systems for lower overall system power requirements.
Note: The C6678 does not support power-down modes for the L2 memory at this time.

More information on the power-down features of the C66x CorePac can be found in the C66x DSP CorePac User Guide.
www.ti.com/.../sprugw0c.pdf

Thanks,

0 Ralf Goebel over 11 years ago in reply to Ganapathi Dhandapani95

Genius 3715 points

Hello,

I created a small project which shows the problem using the TMDXEVM6678L: idletest_evmc6678l.zip

The program normally runs for about 30s and then it creashes. I included my generated .out file because small changes to the memory distribution seem to influence the time until the problem occurs.

Program description:

A worker task peridically calls memset() and Task_sleep(1):

	while (1)
	{
		memset(pBuffer, i, BLOCKSIZE);
		i++;

		if ((i%1000) == 0)
		{
			printf("Woker: %u loops\n", i);
		}

		Task_sleep(1);
	}

The following function implements the CorePac power-down and it gets called when the CPU is idle:

void IdleCPU()
{
	REG(PDCCMD_REG) |= PDCCMD_IDLE; // power-down the CorePac
	asm(" idle");
}

Thanks,
Ralf

0 Ralf Goebel over 11 years ago in reply to Ganapathi Dhandapani95

Genius 3715 points

Hello,

is someone out there able to reproduce this issue?

Thanks,
Ralf

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Hi Ralf,
I've tried to run your attacheda code on C6678EVM board (Shannon) and don't see any problem.
How did you run this code and called gel file ?

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

I'm using the evmc6678l.gel file which comes with CCS (C:\ti\ccsv5\ccs_base\emulation\boards\evmc6678l\gel\evmc6678l.gel). Before loading the program, I issue a System Reset and then I start the following gel function: Scripts -> EVMC6678L Init Functions -> Global_Default_Setup.
The program prints the number of loop iterations on the console and it crashes after about 29000 loops.

Ralf

0 Ganapathi Dhandapani95 over 11 years ago in reply to Ralf Goebel

TI__Mastermind 28085 points

Better to use the latest MCSDK EVM gel file for your testing.
MCSDK Path: \ti\mcsdk_2_01_02_06\tools\program_evm\gel\evmc6678l.gel
For more information refer \ti\mcsdk_2_01_02_06\tools\program_evm\gel\README.txt file.

Also give the power reset to the EVM and repeat your test.

Thanks,

0 Ralf Goebel over 11 years ago in reply to Ganapathi Dhandapani95

Genius 3715 points

The MCSDK .gel file and power reset make no difference for me.

Could there be a difference between the TMDSEVM6678L and the TMDXEVM6678L?

Thanks,
Ralf

0 Ralf Goebel over 11 years ago in reply to Ganapathi Dhandapani95

Genius 3715 points

It seems that the CPU frequency has an impact on stability. My EVM appears stable at 850 MHz. I will make further tests tomorrow.

Ralf

0 Ganapathi Dhandapani95 over 11 years ago in reply to Ralf Goebel

TI__Mastermind 28085 points

TMDSEVM6678L - TMS320C6678 Lite Evaluation Module.
TMDXEVM6678LE - TMS320C6678 Lite Evaluation Module with XDS560V2. Faster emulation allows programmers to load their
application software on the DSP more rapidly.

Thanks,

0 Ralf Goebel over 11 years ago in reply to Ganapathi Dhandapani95

Genius 3715 points

I think the TMDXEVM6678L is using an experimental device TMX320C6678, not TMS...

Ralf

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Hi Ralf,

I'm using the evmc6678l.gel file which comes with CCS (C:\ti\ccsv5\ccs_base\emulation\boards\evmc6678l\gel\evmc6678l.gel). Before loading the program, I issue a System Reset and then I start the following gel function: Scripts -> EVMC6678L Init Functions -> Global_Default_Setup.

I haven't used like this, just locate the *.gel file to core 0 and connect the core 0 then you can see all the peripherals got enabled & initialized.

Could you please attach the screen shot of console o/p when you get the error with loops count o/p.

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

Hi,

I can also run the program without using System Reset with the same result.

This is an example of the console output. The output stops after 9000 cycles:

Woker: 1000 loops
Woker: 2000 loops
Woker: 3000 loops
Woker: 4000 loops
Woker: 5000 loops
Woker: 6000 loops
Woker: 7000 loops
Woker: 8000 loops
Woker: 9000 loops

When trying to halt the CPU, I get the following error:

Thanks,
Ralf

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Hi Ralf,

For me, its simply IDLE function and not worker.

Are you doing something to run "worker" function ?

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

I'm not sure which program you are running, I don't have the console outputs you have.
In my third post I attached the CCS project which should work. The main() function creates a task with the Worker() function. The .zip file also contains the executable file I'm using.

Ralf

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

I've added that printf in "IdleCPU" function.

When I ran that code, simply its running the idle task function and not worked thread.

void IdleCPU()
{
printf("Idle CPU fn executed!\n");

// REG(PDCCMD_REG) = PDCCMD_IDLE;
REG(PDCCMD_REG) |= PDCCMD_IDLE; // preserve the lower 16 bits?
asm(" idle");
}

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

With your modification, the Worker thread still runs, but not very often.
The program seems to be more stable then, but it also crashes after a few minutes.

Ralf

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Hi Ralf,

Ralf said:

When trying to halt the CPU, I get the following error:

What do you mean the "halt" the CPU and how ?

I've tried the following code and able to run all time.

Could you please help us to reproduce your problem.

With your modification, the Worker thread still runs, but not very often.
The program seems to be more stable then, but it also crashes after a few minutes.

It seems to be timing issue !!??

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

/* BIOS6 include */
#include <ti/sysbios/BIOS.h>
#include <ti/sysbios/knl/Task.h>


unsigned int j = 0;


#define BLOCKSIZE (1<<20)

void Worker()
{
    int i = 0;
    unsigned int *pBuffer;

    pBuffer = (unsigned int *)malloc(BLOCKSIZE);
    if (pBuffer == NULL)
    {
        printf("Error: malloc() failed\n");
        return;
    }

	while (1)
	{
		memset(pBuffer, i, BLOCKSIZE);
		i++;

		if ((i%1000) == 0)
		{
			printf("Worker: %u loops; IDLE %d \n", i,j);
		}

		Task_sleep(1);
	}
}


#define REG(x) (*((volatile UInt32 *)(x)))

#define PDCCMD_REG      0x01810000
#define PDCCMD_IDLE     0x00010000

void IdleCPU()
{
//	printf("Idle CPU fn executed!\n");

	j++;

//	REG(PDCCMD_REG) = PDCCMD_IDLE;
	REG(PDCCMD_REG) |= PDCCMD_IDLE;	// preserve the lower 16 bits?
	asm(" idle");
}


//---------------------------------------------------------------------
// Main Entry Point
//---------------------------------------------------------------------
int main()
{
	Task_Params taskParams;

	// Create worker task
	Task_Params_init(&taskParams);
	taskParams.priority = 2;
	taskParams.stackSize = 4096;
	taskParams.instance->name = "Worker";
	Task_create((Task_FuncPtr)Worker, &taskParams, NULL);

	/* Start the BIOS 6 Scheduler */
	BIOS_start();
}

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

By "halting the CPU" I mean going to the menu Run->Suspend.

I also tried the program with our custom hardware using C6678 1.25GHz and C6674 1.0 GHz devices with the same result.

Ralf

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Okay, thanks, you can see from above screen shot, I'm able to "suspend" and not getting any problem.
Have you tried the code in C6670/C6678 EVM board ?

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

I'm using the EVM and I'm not able to suspend the CPU after the console output stops.

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Which emulator are you using ?

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

I have a SD XDS560v2 LC Traveler and a SD XDS560v2 STM.

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Hi,
I'm clue less now.
Have you setup your EVM to "DSP No boot" mode ?

0 Ralf Goebel over 11 years ago in reply to Titusrathinaraj Stalin

Genius 3715 points

Hi,

yes, the EVM is configured to "No Boot" mode.
Are you using the TMDS or the TMDX EVM?

The strange thing is that the problem goes away when reducing the CPU frequency or by placing the .text section into L2SRAM.

I don't want to waste too much of your time. We don't necessarily need CorePac power down. But I have to make sure that we don't have any electrical problem.

Thanks,
Ralf

0 Titusrathinaraj Stalin over 11 years ago in reply to Ralf Goebel

TI__Guru** 116100 points

Hi,
I'm using TMDSEVM6678LE Rev3.B

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C6678: IDLE instruction with Power-down