AWR2243: Questions about AM273X + 2xAWR2243 EVM cascade application

Hello Champs,

It is mentioned that 4.7. How to run 2-Chip cascade application (Applicable for only AM273X + 2xAWR2243 EVM)  in the mmwave_mcuplus_sdk_user_guide.pdf. 

I have below questions needing your help.

1. "2xAWR2243 EVM" means two AWR2243boost EVM boards or two cascaded awr2243 chips on a board?

2. am273x_cascade_mss.xer5f is running on AM273X EVM board, what code need to run on AWR2243boost EVM?

3. Customer wanted to use AWR1243 instead of AWR2243.  What modification he need to do？

Thanks.
Rgds
Shine