EZ-USB ISO transfer

Hi

I have another problem about the EZ-USB AN2131 ISO transfer

I set the EP8 is an out endpoint and the size is 16 bytes. I use following code to receive the data from host.

byteCount = (OUT8BCH << 8) + OUT8BCL;
while (byteCount--){
value = OUT8DATA;
}

the problem is: does the OUT8DATA can increase the address automatically? If not, then I just read the same byte always.
Because I look at the assembly code, it likes this:

MOV DPTR,#OUT8DATA
MOVX A,@DPTR
MOV R7,A

OUT8DATA is never increased.

How to increase the OUT8DATA so that I can read the next byte?

INC DPTR

HEHE... :D