SPI time gap between 2 words

Yaroslav Mudritsky

Intellectual 760 points

Other Parts Discussed in Thread: CC3100, CC3200

Hi all,

I open new topic becouse in my previus topic I've solved my issues.

I want to ask how is possible to remove or reduce time gap (750ns) between 2 consecutive words in an SPI trasmission.

My settings are:

MAP_SPIConfigSetExpClk(SSIBASE,MAP_PRCMPeripheralClockGet(PRCM_GSPI),
20000000, SPI_MODE_MASTER, SPI_MODE0,
(SPI_HW_CTRL_CS |
SPI_3PIN_MODE |
SPI_TURBO_OFF |
SPI_CS_ACTIVELOW |
SPI_WL_8));

and i send data with

MAP_SPITransfer(SSIBASE, &data, &rxData, 10, 0);

over 10 years ago

0 Glenn Vassallo over 10 years ago

Guru 21435 points

Not sure you can, I tried a multitude of different combinations and could not remove the gap, the only time I saw the gap not present was when the speed was slow down significantly.

You can see this thread were I was struggling with this - e2e.ti.com/.../356460

Please note I was using the pre-production firmware, I have not tested with the released firmware.

I assume you are trying to use the SPI MOSI line for a 1 wire solution that does not use the SPI clock and hences will need to sustain perfect timing?

I ended up using the Tiva C LaunchPad and the CC3100 as a solution.

Glenn.

0 Yaroslav Mudritsky over 10 years ago in reply to Glenn Vassallo

Intellectual 760 points

No, I'm using SPI clock but I need to have a higher transfer rate. Have you ever tryed to use CC3200 as slave and trasmitting with no gaps?

0 Glenn Vassallo over 10 years ago in reply to Yaroslav Mudritsky

Guru 21435 points

No, I never tried setting the CC3200 as the Slave. Perhaps this could work if this is possible in your scenario.

Glenn.

0 Praneet Kumar over 10 years ago in reply to Glenn Vassallo

TI__Genius 16370 points

Yaroslav,

As explained in the other thread (e2e.ti.com/.../356460), 'turbo mode' can be used to reduce the idle cycles between transfer of successive words (from 4 idle cycles to 1.5 idle cycles), but it can't be eliminated totally. Please let me know if this meets your requirement.

-/Praneet

0 Praneet Kumar over 10 years ago in reply to Praneet Kumar

TI__Genius 16370 points

I'm closing this thread - For any followup questions that you might have, request you to open a new thread w/ references to the current one for us to track it better.

-/Praneet

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SPI time gap between 2 words