NXP Semiconductors MPC5644A, Reference Manual, Page: 217 / 1735

Flash memory
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 217
Chapter 12
Flash memory
12.1 Introduction
This section presents information about the following components on this device:
• The flash memory blocks
• The platform flash memory controller
The primary function of the flash memory module is to serve as electrically programmable and erasable
non-volatile memory. The NVM memory can be used for instruction and data storage. The block is a
non-volatile solid-state silicon memory device consisting of blocks of single-transistor storage elements,
an electrical means for selectively adding (programming) and removing (erasing) charge from these
elements, and a means of selectively sensing (reading) the charge stored in these elements. The flash is
addressable by word (32 bits) and page (128 bits).
There are two flash array blocks (Flash_A and Flash_B). Within each flash block are two functional units:
the flash core (FC) and the memory interface (MI).
The FC is composed of arrayed non-volatile storage elements, sense amplifiers, row selects, column
selects, charge pumps, and redundancy logic. The arrayed storage elements in the FC are subdivided into
physically separate units referred to as blocks.
The MI contains the registers and logic which control the operation of the FC. The MI is also the interface
to the platform flash bus interface unit (PFBIU).
The flash array’s core has three address spaces: low-address space, mid-address space, and high-address
space (see
Figure 12-1 ).