hi:
I try to use at89s8252 to control tlv1544 using SPI interface.When debug my assemble program use keil,I found SPDR can not capture value,why??

my program:
mov spcr,#01011110b
.........
mov a,#0x90
mov spdr,a
clr cs(breakpoint,spdr=0x00??)
call sample
setb cs