Hardware SPI NSS is not working.

[tonykwon100]

Posted on March 28, 2016 at 12:38

Hello?

I'm using STM32F446RE chip and STM32Cube_FW_F4_V1.7.0 library. I have tried to use hardware SPI NSS(SPI_NSS_HARD_OUTPUT). But, I can't. It's not working.... Would you please inform me how to use hardware nss functionality? Thank you.

[slimen]

Posted on March 30, 2016 at 14:57

Hello kwon.tony.001,

I suggest you to use the last library version STM32Cube_FW_F4_V1.11.0You can refer to the manual

http://www2.st.com/content/ccc/resource/technical/document/reference_manual/4d/ed/bc/89/b5/70/40/dc/DM00135183.pdf/files/DM00135183.pdf/_jcr_content/translations/en.DM00135183.pdf

, exactly in (26.3.5 Slave select (NSS) pin management) section (page 856) to have more idea about configuration hardware SPI NSS.You can also use CubeMX to generate a project with your own configuration.-ForumSTM32-

[tonykwon100]

Posted on April 08, 2016 at 14:41

Thank you for your comment.

But, I can't download the 'STM32Cube_FW_F4_V1.11.0'. Whre can I find? Thank you. Tony Kwon

[slimen]

Posted on April 08, 2016 at 16:07

Hello,

The 'STM32Cube_FW_F4_V1.11.0' library is available :http://www.st.com/web/catalog/tools/FM147/CL1794/SC961/SS1743/LN1897/PF259243Regards

[tonykwon100]

Posted on April 09, 2016 at 13:16

Hello?

I can only download version 1.10 from the address. Anyway, I have tested with v1.10 but, the hardware SPI CS is still not working. Regards, Tony Kwon

[slimen]

Posted on April 11, 2016 at 14:58

Hi,

What did you mean about ''It's not working'' ?We need more details about your problem.Is the software driving working as expected ?

-ForumSTM32-

Regards

[tonykwon100]

Posted on April 20, 2016 at 14:12

Thanks for your reply.

As you know that there are 4 signals(CLK, MOSI, MISO, NSS) in SPI communication we are using.

If I set the hardware SPI NSS option(SPI_NSS_HARD_OUTPUT), the NSS signal must move up and down automatically while the data is transferred. But, the NSS signal is held on just LOW. It's not moving.

Regards,

Tony Kwon

[yhuang]

Posted on April 27, 2016 at 06:04

STM32F427 has similar issues. I got 2 SPI working with NSS, other 2 did not work with NSS. To solve the issue you may assign NSS as GPIO CS.

[valerio2]

Posted on April 27, 2016 at 09:21

I've got the same issue. However the reference manual says

''NSS output enabled (SSM = 0, SSOE = 1)This configuration is used only when the device operates in master mode. TheNSS signal is driven low when the master starts the communication and is keptlow until the SPI is disabled.''So this is not a ''bug''.