A typical sequence for writing to a register using scan chain 7 is as follows:

SCAN_N  7                            ; select ITR

EXTEST

REQ 1stAddr2Wr  1stData2Wr 0b1       ; write request for register 1stAddr2write

FOR(i=2; i <= Words2Write; i++) DO

    LOOP

        REQ ithAddr2Wr ithData2Wr 1 Ready

                                     ; ith write request while waiting

    UNTIL Ready==1                   ; wait until the previous request completes

ENDFOR

LOOP

    REQ 0 0 0 Ready                  ; null request while waiting

UNTIL Ready==1                       ; wait until last request completes