DRA829V: Using FT2232HQ for main UART and MCU UART

Hello all,

Could you please help.. 

Rgds,

Arun

Arun,

Yes you can use FT2232H to multiplex between different UART ports. This is currently done on the EVM. For more information and design recommendation, please reference the EVM schematic and user guide here:  

https://www.ti.com/tool/J721EXSOMXEVM

https://www.ti.com/lit/ug/spruis4b/spruis4b.pdf

Best Regards,

Shiou Mei

Hi Shiou,

Thanks. I understood that in EVM it is multiplexed, but we are planning to multiplex both MCU_UART0 And MAIN_UART0 which is not done in the EVM. Could you please confirm this

Arun

A single FT2232H can be used to support MCU_UART0 and MAIN_UART0.  Depending on how the VDDSHV IO rails are powered, you may need to add buffer/isolation between Processor/FT2232H (especially if supporting MCU-only or similar modes).  Not clear on question regarding binary impact.  The EVM support UARTs for both MCU_UART0 and MAIN_UART0.  It sounds like this design will be same - so no impact.

Hi Robert,

Binary impact i asked is loading the images 

1. tiboot.bin - MCU UART0

2. sysfw.itb - MCU UART0

3. tispl.bin - MAIN UART0

4.uboot.img - MAIN UART0

Will there be impact if MAIN UART0 and MCU UART0 is multiplexed !!

We are not using MCU only mode. We are utilizing both the domains

-Arun

I'm not clear on meaning of MAIN UART0 and MCU UART0 being multiplexed - can you explain?  The FT2232H supports dual UARTs, so is the plan to support these two UARTs on the FT2232H - or do these UARTs share a single port on the FT2232H?

Hello Robert,

In the EVM, MCU_UART0 and WKUP_UART0 are multiplexed through FT2232 and is connected to J43(MCU Domain UART) and similarly another quad device is used to multiplex UART0(Main domain) and is connected to J44 (Main UART). 

We are planning to use a dual port FT2232 and implement MCU_UART0 and UART0 (main domain) in that single chip and connect to a single USB port. 

I would like to know whether this is possible as i see for quad and dual device, the power domains are different.

In another sense, It will be similar as Dual port FTDI, but Instead of WKUP_UART0 we will use UART0.

Thanks,

Arun M

Software is not aware of which FT device the UARTs are connected, thus no software impact if combining MCU UART0 and MAIN UART0 using a single FT2232H device.