ADUC845 SPI slave issue

        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

Transmit 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?