How to get data from SFMA at "External Address Space Read Mode"

Hello everyone,

My question just like the subject i'v posted, I can't find out the read register of

sfma at " External Address Space Read Mode" .How can I got data from external

flash chips?    Do I need to set the port's Alternative mode for sfma like  

" 1st AltMode input at SFMA0I00(P21_2).." or not?

 

I really need ur help ,thanks !