TMS320F28388D: GPIO72 conflict with EMIF1 data line 12 ( boot mode at startup with external RAM in circuit)

Tool/software:

Hello All, 

We are designing an extremely compact board with F28388D , and using a 16bit SDRAM, per user manual the only available pin for "External memory interface 1 data line 12" is GPIO72.

So now having a SDRAM connected to GPIO72, what will happen in start-up to boot mode? will we end up in some unknown boot mode situation? -- If yes, what to do?

For us, we want the application to work like below ideally:

1. Turn ON the device
2. The USB Boot loader looks at a single specific GPIO, if that pin is LOW, we go to DFU mode, if not we load the program from Flash to RAM and execute normally
3. If we are in DFU mode, we will wait for the application to update the firmware through USB
4. if the firmware is updated, we ask the user to recycle the power and put that DFU GPIO in high state
5. After power recycling the device runs with updated Firmware

This is pretty much what we did before with other DSPs ( F28069 ), and it works great.

Having this context in mind, how should we deal with GPIO72 that is shared with EMIF1 ?

John