CC3100MODBOOST: Unexpected sync byte from CC3100

Nikola Bulatovic

Part Number: CC3100MODBOOST
Other Parts Discussed in Thread: CC3100

I am porting SimpleLink driver to STM32 MCU. I ported the host driver before but I haven't seen this. Can anyone please help with understanding the response from the WiFi module.

When connected to MSP development kit, the start sequence looks like this:

SPI Write 4: 65 87 78 56
SPI Read 4: bc dc cd ab

When running on our MCU, the first byte of the response is b9 instead of bc. I manually decoded the scope trace and verified that CC3100 is really sending 0xb9.

SPI Write 4: 65 87 78 56
SPI Read 4: b9 ....

Can anyone tell me what is causing this?

over 2 years ago

+1 Michael Reymond over 2 years ago

TI__Mastermind 40965 points

Hi,

The sync word expected from the CC3100 is always 0xABCDDCBA. Any value other than that indicates some issue with the host interface.

It's interesting that you see the first byte never be 0xba, but instead 0xbc or 0xb9. Seems like there is bit-shifting of the SPI output from the CC3100 for some reason.

What SPI bitrate are you using? If you adjust it down to a very low test value such as 1MHz, do you still see the same issue?

Regards,

Michael

0 Nikola Bulatovic over 2 years ago in reply to Michael Reymond

Prodigy 30 points

thank you, i got it working up to initialization complete

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CC3100MODBOOST: Unexpected sync byte from CC3100