RTOS/SW-EK-TM4C1294XL: The Task in external SRAM get struck in SPI peripheral data transfer

saleem nawaz

Tool/software: TI-RTOS

Hello,

We are using TIRTOS v2_16_01_14 and BIOS version 6_45_02_31. We are using the external SRAM over EPI interface. When we define a statically allocated Task in external SRAM and when trying to communicate with peripheral over SPI interface, sometime the SPI transfer get struck and does not complete.

When we move the same task to internal memory, it works fine with SPI peripheral. We are using the SPI baud rate 10 MHz.

The external SRAM has a speed of 20MHz and the system clock is 120 MHz. The SPI is using uDMA to transfer data.

Can you suggest what could be problem when the task is in external memory and that task has SPI communication functionality with peripheral and it get struck on SPI transfer. This issue occur randomly but it is easily reproducible.

Here is the SPI settings.

SPI_Params_init(&params);
params.transferMode = SPI_MODE_BLOCKING; //SPI_MODE_CALLBACK; //SPI_MODE_BLOCKING;
params.frameFormat = SPI_POL1_PHA1;
params.bitRate = 10000000;
handle = SPI_open(Board_Dataflash_SPI, &params);

Thanks.

over 8 years ago

0 ToddMullanix over 8 years ago

TI__Guru* 96960 points

Hi Saleem,

Where is the data buffer you are trying to send? If the buffer is in the external RAM, can you place it in internal RAM and see if that is more reliable.

Todd

0 saleem nawaz over 8 years ago in reply to ToddMullanix

Intellectual 500 points

Hi Todd,
The data buffer is in external RAM. Once i move the data buffer to internal memory, it is very reliable.

What can be the issue when the buffer is in external RAM. As i already shared the System clock frequency is 120MHz and SRAM is 20MHz.

Thanks.

0 Bob Crosby over 8 years ago in reply to saleem nawaz

TI__Guru 72500 points

If I understand correctly, you have both the task and the transmit buffer in external SRAM interfaced to the EPI. I suspect that the CPU is hogging the access to the AHB bus and preventing the DMA from being able to read the external SRAM. The internal SRAM and flash memory are architected to avoid such a lockout.

0 saleem nawaz over 8 years ago in reply to Bob Crosby

Intellectual 500 points

HI Bob,

Yes i have both Task and Transmit buffer in external SRAM.

Is moving the data buffer in internal memory and keeping task in external SRAM, the only solution to this problem?

Thanks.

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RTOS/SW-EK-TM4C1294XL: The Task in external SRAM get struck in SPI peripheral data transfer