ADUC845 SPI slave issue

ransmit data from slave ADUC845 device don't work. In first trasmition master read 0xAA 0xFF 0xFF 0xFF and in next trasmition 0xFF 0xFF 0xFF 0xFF. Data on SPI readed via logic analyzer simultaneously. Master receieved correctly.

How do i correctly trasmiting?

    ORG	00h
	JMP     main
        
    ORG     3Bh       ;SPI interrupt
    XCH     A, SPIDAT
    RETI
        
main:
    MOV	    PLLCON, #01h	;f core = 6,29MHz, max for 3V ADUC845 device
    MOV	    PCON, #10h	    ;ALE -> OFF
    MOV	    CFG845, #01h	;use internal XRAM
    MOV	    SP, #80h	    ;stack to indirectly adressed memory
    
    MOV     SPICON , #0Ch	;SPI Mode 3, Slave
    MOV	    IEIP2, #11h	    ;SPI interrupt enabled with high priority
        
    SETB    IE_EA           ;interrupts enabled
    SETB    SPICON_SPE      ;SPI -> ON
    MOV     SPIDAT, #0AAh
        
loop:
    MOV     A, #55h
    JMP     loop