FT221XQ-T FTDI, FT221XQ-T Datasheet - Page 35

• Manufacturer Part Number: FT221XQ-T
• Description: USB Interface IC USB to 8 bit SPI / FT1248 IC QFN-20
• Manufacturer: FTDI

Specifications of FT221XQ-T

• Rohs: yes
• Tradename: X-Chip

The information in the rest of this chapter can be used to implement the storing and reading of
application data in the user area as in example 1 above. Example 2 requires details of the configuration
data stored in the MTP memory which is FTDI proprietary information. A separate application note is
available under NDA from FTDI support for customers who require to do this ([e-mail]).
9.3 Memory Map
The FT-X family MTP memory has various areas which come under three main categories:
Figure 9.1: 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
both USB and FT1248 on the FT221X. 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 6.4 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.
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

User Memory Area
Configuration Memory Area (writable)
Configuration Memory Area (non-writable)
Copyright © 2013 Future Technology Devices International Limited
Accessible via USB, I
Accessible via USB, I
Accessible via USB, I
Accessible via USB, I
Configuration Memory Area
Configuration Memory Area
Configuration Memory Area
Memory Area Description
User Memory Area 2
User Memory Area 1
Cannot be written
2
2
2
2
C and FT1248
C and FT1248
C and FT1248
C and FT1248
Document No.: FT_000630 Clearance No.: FTDI# 263
Word Address
0x3FF - 0x80
0x7E - 0x50
0x4E - 0x40
0x3E - 0x12
0x10 - 0x00
Version 1.2
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