The AT49F040 is a 5-volt-only in-system Flash Memory. Its 4 megabits of memory is organized as 524,288 words by 8 bits. Manufactured with Atmel's advanced nonvolatile CMOS technology, the device offers access times to 90 ns with power dissipation of just 275 mW over the commercial temperature range. When the device is deselected, the CMOS standby current is less than 100 A. To allow for simple in-system reprogrammability, the AT49F040 does not require high input voltages for programming. Five-volt-only commands determine the read and programming operation of the device. Reading data out of the device is similar to reading from an EPROM. Reprogramming the AT49F040 is performed by erasing the entire 4 megabits of memory and then programming on a byte by byte basis. The byte programming time is a fast 50 s. The end of a program cycle can be optionally detected by the DATA polling feature. Once the end of a byte program cycle has been detected, a new access for a read or program can begin. The typical number of program and erase cycles is in excess of 10,000 cycles. (continued)