POF is not in the AT89C52. At least it's not included in my well-worn '95 Atmel data book.

Usually I'd say to check the datasheet of the particular derivative, but in this case the AT89C52 datasheet (update 2/2000) only indicates that the PCON SFR exists, and not what its bit assignments might be. No help there, especially when combined with the referenced Atmel 8051 Hardware manual. Very misleading. Oh well, the 89C52 isn't recommended for new designs anyway.

The AT89S52 does indicate that PCON.4 is POF.

Dennis