DRV8353F: Connect 2 SPI ICs with different topology (Push pull and Pull up)

fedi makni

Part Number: DRV8353F

Tool/software:

Hello,

I am willing to use the DRV8353F in my next design.

The device offer to interface using SPI but i saw in the datasheet that SDO (MISO) line require a pull up to function correctly.

The issue is that i have another SPI device connected to the uC but uses the push pull topology.

My question is:

Is it ok to connect both SPI togethers or the pull up resistor on the SDO pin will mess with the communication with the MISO pin of the other IC (the other IC is an ADC)

My logic level is 3.3V

Thank you.

2 months ago

0 Akshay Rajeev Menon 2 months ago

TI__Mastermind 23566 points

Hey Fedi,

I would try to avoid this, as I am not sure if it will work as expected.

Having two chip selects should help when they are activated but when the push pull is connected to GND then there will be excess current from the pull up on DRV SDO line.

I would recommend reaching out to the ADC team and checking if they see any concerns with this implementation as well, but would personally avoid sharing lines.

Best,

Akshay

0 fedi makni 2 months ago in reply to Akshay Rajeev Menon

Prodigy 50 points

The ADC is actually the ADS131M04IPWR which is also a TI part. Do i need to ask in a separate thread or this thread is sufficient?

Of course we will have 2 CS for each IC but the issue when the CS of the ADC is on and CS of the motor driver is off, the pull up resistor in SDO will interfere with the commands received from the ADC.

Do you think i should avoid using both ICs in the same project?

0 Akshay Rajeev Menon 2 months ago in reply to fedi makni

TI__Mastermind 23566 points

Hey Fedi,

Let me loop in the ADC team. Using both in same projects inset the issue but sharing the line is where there might be challenges

Best,

Akshay

0 fedi makni 2 months ago in reply to Akshay Rajeev Menon

Prodigy 50 points

Hello,

Thank you, If the ADC team can provide any tips how i can make them both work on the same bus that can be very helpful.

Will they answer in this thread?

0 fedi makni 1 month ago in reply to fedi makni

Prodigy 50 points

Hello,

Any update on this?

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DRV8353F: Connect 2 SPI ICs with different topology (Push pull and Pull up)