SK-AM62B-P1: Clarification Needed on SoC UART1 FET Switch & Buffer Section in SK-AM62B-P1 Schematic

Arijit Mohanty

Part Number: SK-AM62B-P1

Tool/software:

Hellow Ti experts,

I’m currently designing a custom single-board computer (SBC) based on the SK-AM62B-P1 EVM as a reference. While working on the schematic, I’ve encountered some confusion regarding the SoC UART1 FET switch & buffer section (as shown on page 37 of the EVM schematic).
8176.PROC142A(002)_SCH_With_Design_Updates..Notes_V1.0.pdf

I’ve noticed that signals from SoC_UART1 are routed to multiple blocks:

The FT4232 USB-to-UART bridge section
The user expansion connector
And are also routed through a FET switch/multiplexer, alongside SoC_SPI2 signals.

I’m trying to fully understand the connection topology and purpose of this section:

How is the switching logic controlled?
What determines whether UART1 connects to the FT4232 vs. the expansion connector?
Why are SPI2 and UART1 sharing this switching structure?

A detailed explanation or block-level overview of how this section operates would be greatly appreciated.

Thank you
Arijit

3 months ago

0 Kallikuppa Sreenivasa 3 months ago

TI__Guru**** 189699 points

Hello Arijit

Thank you.

Please read the data sheet pin attributes

Each of the SOC pin provides capability to be able mux multiple functions.

The SK is designed to showcase multiple functions and hence multiple connections.

One of the use case is UART.

Please refer below FAQ

(+) [FAQ] SK-AM62: Purpose Of Different UARTs - Processors forum - Processors - TI E2E support forums

The FET switch is enabled by the IO expander.

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa 3 months ago in reply to Kallikuppa Sreenivasa

TI__Guru**** 189699 points

Hello Arijit

Please summarize the pins and the use case if you needs additional explanation.

Regards,

Sreenivasa

0 Arijit Mohanty 3 months ago in reply to Kallikuppa Sreenivasa

Prodigy 60 points

I’m trying to understand how the SN74CB3Q3257PWR FET bus switch, SN74AVC4T245DGVR level shifter, FT4232 USB-to-UART bridge, and the user expansion connector are connected and work together. Many of the UART and SPI signals seem to be shared across these sections, which is a bit confusing. A clear explanation or block-level overview of how these components are linked and how the signal routing is handled would be very helpful.

Thank you

0 Kallikuppa Sreenivasa 3 months ago in reply to Arijit Mohanty

TI__Guru**** 189699 points

Hello Arijit

Thank you.

They may not work together.

based on the required functionality, you may have to configure the EVM.

Regards,

Sreenivasa