Partition Table Mechanism
Overview
Flash memory can contain various types of data, including applications,user resources. To facilitate the efficient use of flash resources, we propose a partition table solution.
Each entry in the partition table includes the following components: Name (partition name), Offset (offset relative to the flash base address), Size (partition size), and Flag (currently unused).
The default offset address of the W800 partition table is 0xE000, and the size of the partition table is 0x1000 (one sector, 4k).
Attention
The offset and size of the partition table need to be 4K-aligned. Please ensure that when configuring the partition table, the offset and size of each partition are both integer multiples of 4K.
Using the Partition Table
The simplest way to use the partition table is to open the project configuration menu menuconfig and enter the Partition Table menu. In the Partition Table ection, select a partition table. We provide three preset partition tables and one user-defined partition table. Below are the preset partition tables, with the last one being the user-defined partition table.
“Normal app, no OTA (components/partition_table/config/partition_table_normal.csv)”
“Large app, no OTA (components/partition_table/config/partition_table_large.csv)”
“Normal app, with OTA (components/partition_table/config/partition_table_with_ota.csv)”
“Custom partition table (<project directory>/partition_table_custom.csv)”
Built-in Partition Table Styles
Here is a summary of the partition table information for the “partition_table_normal.csv” option:
# name, offset, size, flag
ft, 0x0, 0x2000, 0x0
bootloader, 0x2000, 0xC000, 0x0
partition_table, 0xE000, 0x1000, 0x0
app, 0xF000, 0x100000, 0x0
nvs, 0x1F0000, 0x8000, 0x0
Here is a summary of the partition table information for the “partition_table_large.csv” option:
# name, offset, size, flag
ft, 0x0, 0x2000, 0x0
bootloader, 0x2000, 0xC000, 0x0
partition_table, 0xE000, 0x1000, 0x0
app, 0xF000, 0x1E1000, 0x0
nvs, 0x1F0000, 0x8000, 0x0
Here is a summary of the partition table information for the “partition_table_with_ota.csv” option:
# name, offset, size, flag
ft, 0x0, 0x2000, 0x0
bootloader, 0x2000, 0xC000, 0x0
partition_table, 0xE000, 0x1000, 0x0
app, 0xF000, 0x122A00, 0x0
app_ota, 0x131A00, 0xAE600, 0x0
user, 0x1E0000, 0x2000, 0x0
nvs, 0x1F0000, 0x8000, 0x0
Among these three partition tables, the Normal partition does not include app_ota and user partitions. The SDK defaults to using the Large partition table, but other partition tables can be specified from the Kconfig configuration.
ft partition: Factory firmware for the chip, which will be loaded by default at startup.
bootloader: Stores the bootloader program, which completes the decompression and firmware update of the OTA upgrade file.
partition_table: Stores partition table information, including the name, address, size, and FLAG of each partition.
app: Stores the application program.
app_ota: Stores the OTA upgrade application package.
user: User-defined partition, currently not used by the SDK framework.
Non-volatile storage partition for storing key-value data of the NVS module. Since this partition requires a block for garbage collection, the size of nvs needs to be at least 2*0x1000.
Attention
ft is the factory firmware for the chip, and users cannot modify its content.
Attention
The configuration of the ft, bootloader, and partition_table partitions cannot be modified. The app, app_ota, and nvs partitions cannot change names, but their addresses and sizes can be modified.
User-Defined Partition Table
If you want a partition table with higher flexibility for your program, select the Custom partition table option in the menuconfig under the Partition Table menu. Then, add a partition_table_custom.csv file in the root directory of the project.The build system will automatically recognize and process it during compilation.
Here is a summary of the partition table information for the “Custom partition table” option:
# name, offset, size, flag
ft, 0x0, 0x2000, 0x0
bootloader, 0x2000, 0xC000, 0x0
partition_table, 0xE000, 0x1000, 0x0
app, 0xF000, 0x1D1000, 0x0
user, 0x1E0000, 0x2000, 0x0
nvs, 0x1F0000, 0x8000, 0x0
Spaces between fields will be ignored, and any line beginning with
#(comments) will also be ignored.Each non-comment line in the TXT file defines a partition.
The user partition is an example of a user-configured partition. When using it, you only need to set the offset and size fields appropriately.
The ft, bootloader, and partition_table partitions cannot be changed. The names of the app and nvs partitions cannot be changed, but their addresses and sizes can be modified.
Flashing
After configuring the partition table, the build process will generate a partition_table.img flashing file in the build/partition_table directory. The wm.py flash command will automatically flash this partition file to the configured location.
Erasing
The wm.py flash command with the -e option can erase the entire flash before writing the image.
Compiling Files to Custom Partitions
Please refer to WM-IOS Building System Programming Manual