Chapter 28
SPI NOR Flash Memory Technology Device (MTD)
Driver
28.1 Introduction
The SPI NOR Flash Memory Technology Device (MTD) driver provides the support to
the data Flash though the SPI interface.
By default, the SPI NOR Flash MTD driver creates static MTD partitions to support data
Flash. If RedBoot partitions exist, they have higher priority than static partitions, and the
MTD partitions can be created from the RedBoot partitions.
28.1.1 Hardware Operation
On some boards, the SPI NOR - AT45DB321D is equipped, while on some boards
M25P32 is equipped. Check the SPI NOR type on the boards and then configure it
properly.
The AT45DB321D is a 2.7 V, serial-interface sequential access Flash memory. The
AT45DB321D serial interface is SPI compatible for frequencies up to 66 MHz. The
memory is organized as 8,192 pages of 512 bytes or 528 bytes. The AT45DB321D also
contains two SRAM buffers of 512/528 bytes each which allow receiving of data while a
page in the main memory is being reprogrammed, as well as writing a continuous data
stream.
The M25P32 is a 32 Mbit (4M x 8) Serial Flash memory, with advanced write protection
mechanisms, accessed by a high speed SPI-compatible bus up to 75MHz. The memory is
organized as 64 sectors, each containing 256 pages. Each page is 256 bytes wide. Thus,
the whole memory can be viewed as consisting of 16384 pages, or 4,194,304 bytes. The
memory can be programmed 1 to 256 bytes at a time using the Page Program instruction.
The whole memory can be erased using the Bulk Erase instruction, or a sector at a time,
using the Sector Erase instruction.
i.MX 6Solo/6DualLite Linux Reference Manual, Rev. L3.0.35_4.1.0, 09/2013
Freescale Semiconductor, Inc.
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