CCS/TMS320F28379D: TMS320F28379D SPI via DMA

Sabina Greenberg101872

Expert 2780 points

Part Number: TMS320F28379D

Tool/software: Code Composer Studio

Dear support,

I run two examples: spi_loopback_cpu1 and spi_loopback_dma_cpu1.

In both examples I removed loopback . In spi_loopback_dma_cpu1 I added calling InitSpiGpio() send/read data always:

while(1)

{

StartDMACH6();

StartDMACH5();

}

In the 1st example in see all signals good(1-SPISTEA, 2-SPICLKA, 3-SPISIMOA)

In the 2nd example with DMA I don't see SPISTEA signal and see SPICLKA always

May be I do something wrong? Should I see SPISTEA signal too? We would like to communicate with FPGA via SPI . I think to do it via DMA , but we can not work without SPISTEA signal.

Thanks,Sabina

over 7 years ago

0 Whitney Dewey over 7 years ago

TI__Guru 54885 points

If you look at the DMA registers, does it appear to only be doing a partial transfer? You say you don't see SPICLKA "always"--does that mean the problem shows up inconsistently or you never get a signal on SPICLKA?

Whitney

0 Sabina Greenberg101872 over 7 years ago in reply to Whitney Dewey

Expert 2780 points

I never get a signal on SPISTEA

With DMA:(1-SPISTEA, 2-SPICLKA, 3-SPISIMOA)

Without DMAA:

0 Sabina Greenberg101872 over 7 years ago in reply to Sabina Greenberg101872

Expert 2780 points

Could you help us with this problem, please?

0 Whitney Dewey over 7 years ago in reply to Sabina Greenberg101872

TI__Guru 54885 points

Does the enable line eventually go high again after all the data has been transmitted? The hardware won't deassert the SPISTE line if the words are being sent back-to-back. It only deasserts it if there is sufficient time between transmissions (which is the case in the non-DMA example since it is sending one word at a time).

If your slave device requires a different chip select scheme than what our hardware provides, you will need to use a GPIO controlled by software to assert it.

Whitney

C2000™︎ microcontrollers

C2000 microcontrollers forum

CCS/TMS320F28379D: TMS320F28379D SPI via DMA