54 lines
2.1 KiB
Markdown
54 lines
2.1 KiB
Markdown
# Wear levelling example
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(See the README.md file in the upper level 'examples' directory for more information about examples.)
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This example demonstrates how to use wear levelling library and FATFS library to store files in a partition inside SPI flash. Example does the following steps:
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1. Use an "all-in-one" `esp_vfs_fat_spiflash_mount` function to:
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- find a partition in SPI flash,
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- initialize wear levelling library using this partition
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- mount FAT filesystem using FATFS library (and format the filesystem, if the filesystem can not be mounted),
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- register FAT filesystem in VFS, enabling C standard library and POSIX functions to be used.
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2. Create a file using `fopen` and write to it using `fprintf`.
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3. Open file for reading, read back the line, and print it to the terminal.
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Wear levelling partition size is set in partitions_example.csv file. See [Partition Tables](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/partition-tables.html) documentation for more information.
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## How to use example
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### Hardware required
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This example does not require any special hardware, and can be run on any common development board.
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### Build and flash
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Build the project and flash it to the board, then run monitor tool to view serial output:
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```
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idf.py -p PORT flash monitor
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```
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(Replace PORT with serial port name.)
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(To exit the serial monitor, type ``Ctrl-]``.)
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See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
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## Example output
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Here is an typical example console output.
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```
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I (280) example: Mounting FAT filesystem
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W (440) vfs_fat_spiflash: f_mount failed (13)
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I (440) vfs_fat_spiflash: Formatting FATFS partition, allocation unit size=4096
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I (660) vfs_fat_spiflash: Mounting again
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I (660) example: Opening file
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I (910) example: File written
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I (910) example: Reading file
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I (920) example: Read from file: 'written using ESP-IDF v3.1-dev-171-gf9ad17eee-dirty'
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I (920) example: Unmounting FAT filesystem
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I (1000) example: Done
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```
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To erase the contents of wear levelling partition, run `idf.py erase_flash` command. Then upload the example again as described above.
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