添加智能灯固件代码

firmware/esp-idf/wumei-smart-firmware/examples/storage/semihost_vfs/README.md

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+# Semihosting VFS driver example
+
+(See the README.md file in the upper level 'examples' directory for more information about examples.)
+
+This example demonstrates how to use semihosting VFS driver with ESP32. Example does the following steps:
+
+1. Uses `esp_vfs_semihost_register` function to register exposed host directory in VFS, enabling C standard library and POSIX functions to be used.
+2. Redirects `stdout` from the UART to the file on the host using `freopen`.
+3. Prints several messages to the redirected.
+4. Switches back to UART `stdout` using `freopen`.
+5. Opens text file on the host.
+6. Reads the file and prints its content on stdout.
+
+## How to use example
+
+### Hardware and tools required
+
+This example does not require any special hardware, and can be run on any common development board.
+This example requires [OpenOCD](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/jtag-debugging/index.html#run-openocd).
+NOTE: In order to run this example you need OpenOCD version `v0.10.0-esp32-20190313` or later.
+
+Run OpenOCD using command:
+```
+bin/openocd -s share/openocd/scripts -c 'set ESP_SEMIHOST_BASEDIR '$IDF_PATH/examples/storage/semihost_vfs/data -f board/esp32-wrover-kit-3.3v.cfg
+```
+This command also configures OpenOCD to expose example project `data` subdirectory to the target's semihosting VFS driver.
+
+### Build and flash
+
+Replace PORT with serial port name:
+
+```
+idf.py -p PORT flash monitor
+```
+
+(To exit the serial monitor, type ``Ctrl-]``.)
+
+See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
+
+## Example output
+
+There are two types of outputs produced by example: 
+1. File `esp32_stdout.txt` in the host directory mounted to the target:
+
+```
+W (274) example: Switched to semihosted stdout
+Semihosted stdout write 0
+Semihosted stdout write 1
+Semihosted stdout write 2
+...
+Semihosted stdout write 98
+Semihosted stdout write 99
+W (274) example: Switch to UART stdout
+```
+
+2. On the boards console:
+
+```
+W (274) example: Switch to semihosted stdout
+W (274) example: Switched back to UART stdout
+I (274) example: Wrote 2798 bytes
+====================== HOST DATA START =========================
+The following are the graphical (non-control) characters defined by
+ISO 8859-1 (1987).  Descriptions in words aren't all that helpful,
+but they're the best we can do in text.  A graphics file illustrating
+the character set should be available from the same archive as this
+file.
+
+Hex Description                 Hex Description
+
+20  SPACE
+...
+7D  RIGHT CURLY BRACKET         FD  SMALL LETTER Y WITH ACUTE
+7E  TILDE                       FE  SMALL LETTER THORN (Icelandic)
+                                FF  SMALL LETTER Y WITH DIAERESIS
+====================== HOST DATA END =========================
+I (694) example: Read 6121 bytes
+```
+