FT240X USB 8-BIT FIFO IC Datasheet
Version 1.3
Document No.: FT_000626 Clearance No.: FTDI# 259
8.3 Memory Map
The FT-X family MTP memory has various areas which come under three main categories:
User Memory Area
Configuration Memory Area (writable)
Configuration Memory Area (non-writable)
Memory Area Description
Word Address
0x3FF - 0x80
User Memory Area 2
Accessible via USB
Configuration Memory Area
Accessible via USB
0x7E - 0x50
0x4E - 0x40
0x3E - 0x12
0x10 - 0x00
Configuration Memory Area
Cannot be written
User Memory Area 1
Accessible via USB
Configuration Memory Area
Accessible via USB
Figure 8.1: Simplified memory map for the FT-X
User Memory Area
The User Memory Areas are highlighted in Green on the memory map. They can be read and written via
USB on the FT240X. All locations within this range are freely programmable; no areas have special
functions and there is no checksum for the user area.
Note that the application should take into account the specification for the number of write cycles in
Section 5.4 if it will be writing to the MTP memory multiple times.
Configuration Memory Area (writable)
This area stores the configuration data for the device, including the data which is returned to the host in
the configuration descriptors (e.g. the VID, PID and string descriptions) and also values which set the
hardware configuration (the signal assigned to each CBUS pin for example).
These values can have a significant effect on the behaviour of the device. Steps must be taken to ensure
that these locations are not written to un-intentionally by an application which is intended to access only
the user area.
This area is included in a checksum which covers configuration areas of the memory, and so changing
any value can also cause this checksum to fail.
Configuration Memory Area (non-writable)
This is a reserved area and the application should not write to this area of memory. Any attempt to write
these locations will fail.
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