CC3220 Datasheet, PDF (61/84 Pages) Texas Instruments – SimpleLink Wi-Fi Wireless and Internet-of-Things Solution, a Single-Chip Wireless MCU

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CC3220
SWAS035A – SEPTEMBER 2016 – REVISED FEBRUARY 2017
5.8 Memory
5.8.1 External Memory Requirements
The CC3220x device maintains a proprietary file system on the sFLASH. The CC3220x file system stores
the MCU binary, service pack file, system files, configuration files, certificate files, web page files, and user
files. By using a format command through the API, users can provide the total size allocated for the file
system. The starting address of the file system cannot be set and is always at the beginning of the
sFLASH. The applications microcontroller must access the sFLASH memory area allocated to the file
system directly through the CC3220x file system. The applications microcontroller must not access the
sFLASH memory area directly.
The file system manages the allocation of sFLASH blocks for stored files according to download order,
which means that the location of a specific file is not fixed in all systems. Files are stored on sFLASH
using human-readable filenames rather than file IDs. The file system API works using plain text, and file
encryption and decryption is invisible to the user. Encrypted files can be accessed only through the file
system.
All file types can have a maximum of 100 supported files in the file system. All files are stored in 4-KB
blocks and thus use a minimum of 4KB of flash space. Fail-safe files require twice the original size and
use a minimum of 8KB. Encrypted files are counted as fail-safe in terms of space. The maximum file size
is 1MB.
Table 5-4 lists the minimum required memory consumption under the following assumptions:
• System files in use consume 64 blocks (256KB).
• Vendor files are not taken into account.
• MCU code is taken as the maximal possible size for the CC3220 with fail-safe enabled to account for
future updates, such as through OTA.
• Gang image:
– Storage for the gang image is rounded up to 32 blocks (meaning 128-KB resolution).
– Gang image size depends on the actual content size of all components. Additionally, the image
should be 128-KB aligned so unaligned memory is considered lost. Service pack, system files, and
the 128-KB aligned memory are assumed to occupy 256KB.
• All calculations consider that the restore-to-default is enabled.
ITEM
File system allocation table
System and configuration files⁽¹⁾
Service Pack⁽¹⁾
MCU Code⁽¹⁾
Gang image size
Total
Minimal flash size⁽²⁾
Recommended flash size⁽²⁾
(1) Including fail-safe.
(2) For maximum MCU size.
space
Table 5-4. Recommended Flash Size
CC3220R and CC3220S [KB]
20
256
264
512
256 + MCU
1308 + MCU
16MBit
16MBit
CC3220SF [KB]
20
256
264
2048
256 + MCU
2844 + MCU
32MBit
32MBit
NOTE
The maximum supported sFLASH size is 32MB (256Mb). Please refer to Using Serial Flash
on CC3120/CC3220 SimpleLink™ Wi-Fi® and Internet-of-Things Devices.
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