AT29BV040A

The AT29BV040A is a 3-volt-only in-system Flash Programmable and Erasable Read Only Memory (PEROM). Its 4 megabits of memory is organized as 524,288 words by 8 bits. Manufactured with Atmel's advanced nonvolatile CMOS EEPROM technology, the device offers access times up to 250 ns, and a low 54 mW power dissipation. When the device is deselected, the CMOS standby current is less than 20  A. The device endurance is such that any sector can typically be written to in excess of 10,000 times. The programming algorithm is compatible with other devices in Atmel's 2.7-volt-only Flash memories.

To allow for simple in-system reprogrammability, the AT29BV040A does not require high input voltages for programming. The device can be operated with a single 2.7V to 3.6V supply. Reading data out of the device is similar to reading from an EPROM. Reprogramming the AT29BV040A is performed on a sector basis; 256-bytes of data are loaded into the device and then simultaneously programmed.

During a reprogram cycle, the address locations and 256-bytes of data are captured at microprocessor speed and internally latched, freeing the address and data bus for other operations. Following the initiation of a program cycle, the device will automatically erase the sector and then program the latched data using an internal control timer. The end of a program cycle can be detected by DATA polling of I/O7. Once the end of a program cycle has been detected, a new access for a read or program can begin.