PXS20RM Datasheet, PDF (551/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Chapter 23
Flash Memory
Flash Memory
23.1 Flash memory block (C90FL)
23.1.1 C90FL block overview
The primary function of the C90FL flash memory block is to serve as electrically programmable and
erasable Non-Volatile Memory (NVM). The NVM can be used for instruction and/or 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
C90FL is addressable by word (32 bits) and page (128 bits).
The C90FL block is arranged as two functional units. The first functional unit is the C90FL Flash Core
(FC). The FC is composed of arrayed non-volatile storage elements, sense amplifiers, row selects, column
selects and charge pumps. The arrayed storage elements in the FC are subdivided into physically separate
units referred to as blocks.
The second functional unit of the C90FL is the Memory Interface (MI). The MI contains the registers and
logic which control the operation of the FC. The MI is also the interface to the PFlash Bus Interface Unit
(PFLASH_C90FL).
The PFLASH_C90FL interfaces the system bus on this device to the C90FL memory block. The PFlash
BIU is described in Section 23.2, Dual-ported platform flash memory controller (PFLASH2P).
The base address for the flash bus and flash registers is 0xC3F8_8000.
There are three address spaces:
• Low address space (256 KB)
• Mid address space (256 KB)
• High address space (512 KB)
For block configurations overview see Figure 23-1.
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
23-1