The PIC18F25K22-I/SO is a 8-bit low-power High-performance Microcontroller with XLP technology. This family introduces design enhancements that make these microcontrollers a logical choice for many high performance, power sensitive applications. The flash program memory is readable, writable and erasable during normal operation over the entire VDD range. A read from program memory is executed one byte at a time. A write to program memory is executed on blocks of 64bytes at a time. Program memory is erased in blocks of 64bytes at a time. A bulk erase operation cannot be issued from user code. The data EEPROM is a non-volatile memory array, separate from the data RAM and program memory, which is used for long-term storage of program data. It is not directly mapped in either the register file or program memory space but is indirectly addressed through the special function registers (SFRs). The EEPROM is readable and writable during normal operation over the entire VDD range.