Hi:
I get a problem when I use the ¡®sector erase¡¯ function of P89lv51rd2FA mcu¡¯s IAP.

Once the mcu calls the PGM_MTP with the parameters of ¡®R1 = 08h, DPH = sector address MSB, DPL =sector address LSB¡¯, it will never return to the user¡¯s routines unless reset the mcu by a hardware reset. After that I read out the ROM and find that the calling dose erase the specifically sector.
The other functions of IAP such as ¡®Read User Code¡¯ work well.

My ¡®sector erase¡¯ routines are as follows:

IAP_Erase_PAGE:
PUSH ACC
PUSH DPH
PUSH DPL
MOV R1,#08H
ANL 0B1H,#0FCH
MOV DPH, #MSB
MOV DPL,#LSB
LCALL 1FF0H
MOV R7,A
ORL 0B1H,#01H
POP DPL
POP DPH
POP ACC
RET
END

They are located at 0x2000 and I¡¯m sure the sector to be erased contains no routines so the erasing makes no affect to the whole program. The boot loader is ¡®P89V51RD2_BL_V05¡¯ from Phillips¡¯ web site.

Here come my questions:
1. Is it my ¡®sector erase¡¯ routines or the boot loader or the MCU¡¯s problem which causes the ¡®not returning¡¯ problem?
2. How can I get out of the ¡®sector erase¡¯ IAP function without RESET?