Can I send HCI commands over SPI?

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PaBo_4310606
Level 2
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First like received Welcome!

Hello,

I'm working with BCM20736S which communicates with a host controller over SPI. I'm trying enter BLE Direct Test Mode which as far as I understand is only accessible via sending HCI commands directly.

I was able to use the mode over UART via the Bluetooth Test tool and now I'm trying to incorporate the tests into our main application.

This post answers my question but the hci_control_test.c. is not available for the WICED Smart 2.2.3 which is the latest, but now obsolete, version that supports BCM20736S.

Enabling BLE Direct Test Mode from WICED-Studio application

I was able to find the file in the latest WICED Studio and am trying to back-port it to our application. However it appears to still send the HCI commands over UART and not SPI.

Is there a way to send HCI over SPI?

Thanks

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1 Solution
SheetalJ
Moderator
Moderator
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First comment on KBA 750 replies posted 500 likes received

Hi PaBo_4310606​,

Unfortunately, HCI commands cant be sent over SPI.

View solution in original post

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5 Replies
SheetalJ
Moderator
Moderator
Moderator
First comment on KBA 750 replies posted 500 likes received

Hi PaBo_4310606​,

Unfortunately, HCI commands cant be sent over SPI.

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Hi Sheetal,

Thanks for your reply.

In that case, is there any way to enter Direct Test Mode over SPI or to start individual tests?

Also, is that the case with all HCI commands or is it vendor specific? For example, can I use WICED HCI commands over SPI, assuming the module supports them?

Just to clarify, I'm not looking to send HCI commands directly over SPI, but rather to ask the MCU to send HCI commands to BLE controller. so I guess that will be in a library code?

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I think below threads should clarify the answer you are looking for:

HCI commands over SPI

Re: SPI control by external MCU

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Thanks for referring me to the posts. It seems it's a no go for HCI over SPI but one thing I picked up on this thread - Re: SPI control by external MCU- the answer says HCI is not supported on either SPI or UART for BCM20736 but I was able to run the WICED Bluetooth Test Tool on BCM20736S without any code edits. The tool sends HCI commands over UART which suggests HCI is supported.

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As mentioned in the other post-

"outside of the tools we provide and describe in the Manufacturing Bluetooth Test Tool Application Note (SDK 2.x and TAG3/4 Board), we do not support direct HCI layer access on the BCM2073X or BCM2073XS families."

It implies that you cannot send all the HCI commands then.