TMS320F280039: Running from RAM not improving speed

Sandeep K32

Prodigy 120 points

Part Number: TMS320F280039
Other Parts Discussed in Thread: C2000WARE

It is a 3 phase inverter application.

Main control loop executed in pwm1 interrupt.

#pragma CODE_SECTION(EPWM_INV_ISR, "ramfuncs"); //for placing ISR to RAM

//#pragma CODE_SECTION(EPWM_INV_ISR, ".TI.ramfunc"); //tried this too, same result

When downloading to RAM (no flash debug), the function takes ~20uS. //F280039_ram_lnk,cmd

Time measurement done by driving a GPIO pin at entry and resetting at exit.

When using flash, still with ISR running from RAM, it takes 25uS, big difference.

from linker CMD.

#else //using COFF
.TI.ramfunc : LOAD = FLASH_BANK1_SEC29,
RUN = RAMGS12,
LOAD_START(_RamfuncsLoadStart),
LOAD_SIZE(_RamfuncsLoadSize),
LOAD_END(_RamfuncsLoadEnd),
RUN_START(_RamfuncsRunStart),
RUN_SIZE(_RamfuncsRunSize),
RUN_END(_RamfuncsRunEnd),
ALIGN(8)
#endif

Any help please?
How to ensure, the ISR is running from RAM only?

Regards

Sandeep

over 2 years ago

0 Ozino Odharo over 2 years ago

TI__Mastermind 21416 points

Hi Sandeep,

I'll recommend you check this E2E post that explains how to go about copying code from flash and running from RAM.

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/878674/faq-flash---how-to-modify-an-application-from-ram-configuration-to-flash-configuration

I want to confirm if you're using a Flash linker command file and device.c, device.h and driverlib.h provided in c2000Ware.

Can you confirm that you have the memcpy() directives

e.g. memcpy(&RamfuncsRunStart, &RamfuncsLoadStart, (size_t)&RamfuncsLoadSize);

Regards,

Ozino

0 Sandeep K32 over 2 years ago in reply to Ozino Odharo

Prodigy 120 points

Yes, I am using those files, my application started with a C2000 example and added other functions.
memcy is there in the sysctrl.c, not changed anything in sysctrl.

Though I've defined various functions, for ramfuncs, load size (_RamfuncsLoadSize) not changing, it is just 29.
Loadstart and RunStart matching with flash and ram addresses.

If I remove #pragma also, loadsize not changing.

#pragma CODE_SECTION(EPWM_INV_ISR, ".TI.ramfunc"); //for placin

Using standard cmd file in the example project.

What am I missing?

Regards

Sandeep

0 Sandeep K32 over 2 years ago in reply to Sandeep K32

Prodigy 120 points

The problem found was, pragma statement should be in the same file where the function is.

I kept all the pragma statements in main.c, so was not actually doing anything. No warnings/ errors, just it ignores.

By moving the pragma statement to each file where the function code is, sorted the issue.

btw, program using COFF option, not eabi.

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F280039: Running from RAM not improving speed