TDC7200EVM: Can chip select (CSB) be held low?

Marco Guerreiro

Part Number: TDC7200EVM
Other Parts Discussed in Thread: TDC7200

I am trying to interface with the TDC7200 with a minimum amount of GPIOs. When I toggle the chip select pin (CSB) between commands, the TDC works fine. However, it seems that the TDC does not respond if the chip select (CSB) is held low at all times.

Is it required to toggle the chip select pins between commands?

Regards,

over 6 years ago

0 Scott Cummins over 6 years ago

TI__Mastermind 31655 points

Hello,

Yes, the CSB must go high at the end of a command, so it cannot be held low at all times. The TDC7200 relies on the transitions to prepare for new SPI transactions.

Regards,

0 Marco Guerreiro over 6 years ago in reply to Scott Cummins

Prodigy 195 points

Thanks for answering.

Not that I have used a lot of SPI devices, but this is the first where this is required. Just out of curiosoty, is there a more specific reason to this?

Regards,
Marco

0 Scott Cummins over 6 years ago in reply to Marco Guerreiro

TI__Mastermind 31655 points

It is basically required as a way to ensure good transactions in case something went wrong in a previous transaction. If a transaction is initiated and something goes wrong, instead of potentially carrying over to the next transaction the TDC7200 resets everything on the high to low transition so there is no interference.

Regards,

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TDC7200EVM: Can chip select (CSB) be held low?