Pull-up or pull-down resistors needed for the SPI Interface with the PocketBeagle?

[An Ra]

Hi all,

 

I am working on connecting an ADXL357 accelerometer using the SPI interface with the PocketBeagle.

I will only have one slave device connected on the SPI bus

 

My question is: do I need pull-up or pull-down resistors on any of the SPI interface? If yes, where to connect them and which value ranges should these resistors have? 

Google results were a bit confusing as I found a lot of explanations.

 

Thanks.

[Robert Nelson]

You shouldn't need them for SPI..

Take a look at mikroe's schematic for the ADXL345

https://download.mikroe.com/documents/add-on-boards/click/accel/accel-click-manual-v100.pdf

Regards,

--
Robert Nelson
https://rcn-ee.com/

[evilwulfie]

SPI is not an open collector bus like I2C and pullups are not needed

[An Ra]

Thank you both for the prompt answer. 

[An Ra]

Thanks Robert, the schematics helped a lot. 

[An Ra]

Could somebody please check my first post from 11 days ago with no response.

Thanks. 

On Thursday, July 19, 2018 at 4:58:51 PM UTC-4, An Ra wrote:

[Robert Nelson]

On Fri, Jul 20, 2018 at 10:42 AM, An Ra <arad...@uncc.edu> wrote:
> Could somebody please check my first post from 11 days ago with no response.

Why does it need a response, you answered it yourself...

" Due to the dropout behavior of the LDO TL5209, its output voltage
rail SYS_VDD1_3P3V should not be used when the OSD335x is being
powered through VIN_BAT. Please refer to the TL5209 datasheet for
details."

[An Ra]

Supplying an IC that requires 3.3V or more with the output of the TL5209 is definitely not the right choice as:

3.7V (min battery voltage) - 0.06V (typical value of the battery switch dropout voltage V_DO,BAT of the PMIC (p. 9)) - 500mV (voltage dropout of the LDO @f ull load of 500mA) = 3.14V 

However the 3.14V is inside the range mentioned in the datasheet for supplying the IC (2.7V to 3.6V). That's why I am still confused.