The Pm39F010/020/040 are 1 Mbit/2 Mbit/4 Mbit 5.0 Volt-only Flash Memories. These devices are designed to use a single low voltage, range from 4.5 Volt to 5.5 Volt, power supply to perform read, erase and program operations. The 12.0 Volt VPP power supply for program and erase operations are not required. The devices can be programmed in standard EPROM programmers as well. The memory arrays of Pm39F010/020/040 are divided into uniform 4 Kbyte sectors or uniform 64 Kbyte blocks (sector group - consists of sixteen adjacent sectors). The sector or block erase feature allows users to flexibly erase an memory area as small as 4 Kbyte or as large as 64 Kbyte by one single erase operation without affecting the data in others. The chip erase feature allows the whole memory array to be erased in one single erase operation. The devices can be programmed on a byte-by-byte basis after performing the erase operation. The devices have a standard microprocessor interface as well as a JEDEC standard pin-out/command set. The program operation is executed by issuing the program command code into command register. The internal control logic automatically handles the programming voltage ramp-up and timing. The erase operation is executed by issuing the chip erase, block, or sector erase command code into command register. The internal control logic automatically handles the erase voltage ramp-up and timing. The preprogramming on the array which has not been programmed is not required before an erase operation. The devices offer Data# Polling and Toggle Bit functions, the progress or completion of program and erase operations can be detected by reading the Data# Polling on I/O7 or the Toggle Bit on I/O6.