You can do it with other 8052 that runs faster.
The main loop will be somethink like this:

loop:
mov a,Px ; 1 cycle
movx @dptr,a ; 2 cycles
inc dptr ; 2 cycles
jnb stop_bit,loop ;2 cycles

You need a cycle of 1/9 of microsecond
is enought with a dallas 4 clock cycle and more 25 MHz.
When you finish the scan you can trasmit the datas serially.