Samsung S3F80JB - Manual (Page 290)

S3F80JB EMBEDDED FLASH MEMORY INTERFACE
15-11
SECTOR_ERASE:
LD R12,SecNumH
LD R14,SecNumL
MULT RR12,#80H ; Calculation the base address of a target sector
MULT RR14,#80H ; The size of one sector is 128-bytes
ADD R13,R14
; BTJRF FLAGS.7,NOCARRY
; INC R12
NOCARRY:
LD R10,R13
LD R11,R15
ERASE_START:
SB1
LD FMUSR,#0A5H ; User program mode enable
LD FMSECH,R10 ; Set sector address
LD FMSECL,R11
LD FMCON,#10100001B ; Select erase mode enable & Start sector erase
ERASE_STOP:
LD FMUSR,#00H ; User program mode disable
SB0
RET