This application note provides library source code in C for the M29F400 and the M29W400 Flash memories. The M29W400, with a rated power supply of 3V, is a low voltage version of the M29F400 whose power supply is rated at 5V. The M29W400 has slightly slower access times than the M29F400, but the two devices are otherwise very similar. This application note supports both devices and all technical information about the M29F400 also applies to the M29W400, except where otherwise specified. There are two different M29F400 parts, the M29F400B and M29F400T, which will be referred to generically as the M29F400. Similarly the term M29W400 in this application note can refer to either the M29W400T or the M29W400B.