Hi Bitmasters!
Could anybody point out a good link or give some words describing dual dptr ideology? As i understand, all operations on DPTR access registers depending of the select bit state (WMCON.2 in case of AT89LS8252). Somehow i still can't make it work. Code like this writes a value in DPTR0 then switces to DPTR1, writes different value in the register in question and switches back. If i am right, i should get original value that was left in DPTR0. But..i get a spoiled register. Any ideas?
Thanks!

mov dptr,#SoundAddr ; sound adr to be used later
mov a,WMCON
setb acc.2 ; select DPTR1
mov WMCON,a
mov a,#PWRUP ; start ISD4002 device
call write_spi_byte ; write it to SPI device (will disturb DPTR)
mov a,WMCON
clr acc.2 ; back to DPTR0
mov WMCON,a

;DPTR does not contain SoundAddr any more !!!???