SST89E564, SST89V564, SST89E554, and SST89V554 are members of the FlashFlex51 family of 8-bit microcontrollers. The FlashFlex51 is a family of microcontroller products designed and manufactured on the state-of-the-art Super- Flash CMOS semiconductor process technology. The device uses the same powerful instruction set and is pin-forpin compatible with standard 8xC5x microcontroller devices. The device comes with 72/40 KByte of on-chip flash EEPROM program memory using SST’s patented and proprietary CMOS SuperFlash EEPROM technology with the SST’s field-enhancing, tunneling injector, split-gate memory cells. The SuperFlash memory is partitioned into 2 independent program memory blocks. The primary Super- Flash Block 0 occupies 64/32 KByte of internal program memory space and the secondary SuperFlash Block 1 occupies 8 KByte of internal program memory space. The 8-KByte secondary SuperFlash block can be mapped to the lowest location of the 64/32 KByte address space; it can also be hidden from the program counter and used as an independent EEPROM-like data memory. The flash memory blocks can be programmed via a standard 87C5x OTP EPROM programmer fitted with a special adapter and firmware for SST’s device. During the power-on reset, the device can be configured as a slave to an external host for source code storage or as a master to an external host for In-Application Programming (IAP) operation. The device is designed to be programmed “In-System” and “In-Application” on the printed circuit board for maximum flexibility. The device is pre-programmed with an example of bootstrap loader in the memory, demonstrating the initial user program code loading or subsequent user code updating via the “IAP” operation. An example of bootstrap loader is for the user’s reference and convenience only. SST does not guarantee the functionality or the usefulness of the sample bootstrap loader. Chip-Erase or Block-Erase operations will erase the pre-programmed sample code. In addition to 72/40 KByte of SuperFlash EEPROM program memory on-chip, the device can address up to 64 KByte of external program memory. In addition to 1024 x 8 bits of on-chip RAM, up to 64 KByte of external RAM can be addressed. SST’s highly reliable, patented SuperFlash technology and memory cell architecture have a number of important advantages for designing and manufacturing flash EEPROMs. These advantages translate into significant cost and reliability benefits for our customers.