topic Re: LPC51U68 How to wire SDA line for TDM transmit function in LPC Microcontrollers

LPC51U68 How to wire SDA line for TDM transmit function

Kodai — Tue, 15 Jul 2025 06:05:41 GMT

Hi, I am using LPC51U68 on which I would like to implement TDM transmit function.

I need 4 slots within a frame.

However, LPC51U68 has only one channel pair within a Flexcomm interface.

Therefore, I'm assuming I need to use two Flexcomm interfaces in order to implement 4 slots TDM transmit function.

In this case, is it correct to directly wire Flexcomm 6 SDA pin and Flexcomm 7 SDA pin outside the MCU in order to form single SDA line?

Re: LPC51U68 How to wire SDA line for TDM transmit function

Alice_Yang — Thu, 17 Jul 2025 10:53:54 GMT

Hello @Kodai

Thanks for your question.

Yes, your understanding is generally correct. You can Directly connecting the SDA pins of two Flexcomm interfaces.

If still have any question, please feel free to contact us. Thank you.

Alice

Re: LPC51U68 How to wire SDA line for TDM transmit function

Kodai — Tue, 22 Jul 2025 06:40:46 GMT

Hi, @Alice_Yang .

Thank you for your reply. I'd like to ask you another question.

Does that mean when Flexcomm 6 is sending the data and Flexcomm 7 is not, the SDA pin of Flexcomm 7 is automatically set to high impedance?

Thank you.

Re: LPC51U68 How to wire SDA line for TDM transmit function

Alice_Yang — Wed, 23 Jul 2025 10:00:53 GMT

Hello @Kodai

I believe the answer is yes, but I haven’t found explicit confirmation in the User Manual yet. I’ll help you create a private ticket and verify this internally. Once I receive an update, I’ll reply to you directly on the new ticket.

Thank you!

Alice