Merge branch 'doc/broken_readme_links_v4.0' into 'release/v4.0'

Docs: Fix broken README links (v4.0)

See merge request espressif/esp-idf!9503

examples/bluetooth/bluedroid/ble/blufi/README.md

@@ -3,11 +3,11 @@ ESP-IDF Blufi demo
 
 This is the demo for bluetooth config wifi connection to ap.
 
-To test this demo, you need to prepare a mobile phone with blufi application installed. You can download the blufi application from [Android version](https://github.com/EspressifApp/EspBlufi) and [iOS version](https://itunes.apple.com/cn/app/espblufi/id1450614082?mt=8). 
+To test this demo, you need to prepare a mobile phone with blufi application installed. You can download the blufi application from [Android version](https://github.com/EspressifApp/EspBlufi) and [iOS version](https://itunes.apple.com/cn/app/espblufi/id1450614082?mt=8).
 
 Blufi is completely open source, here is the download link:
 
-* [blufi source code](https://github.com/espressif/esp-idf/tree/master/examples/bluetooth/blufi)
+* [blufi source code](https://github.com/espressif/esp-idf/tree/master/examples/bluetooth/bluedroid/ble/blufi)
 
 * [BluFi protocol](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/blufi.html?highlight=blufi#the-frame-formats-defined-in-blufi)
 

examples/bluetooth/bluedroid/coex/gattc_gatts_coex/README.md

@@ -5,10 +5,10 @@ This example demonstrates the coexistence of gattc and gatts.
 
 This example creates a GATT service and starts ADV. The ADV name is `ESP_GATTS_DEMO`, then waits to be connected. At the same time, a gatt client is created, the ADV name is `ESP_GATTS_DEMO`, the device is connected, and the data is exchanged. If the device is not found within 120 seconds, the example will stop scanning.
 
-ESP-IDF also allows users to create a GATT service via an attribute table, rather than add attributes one by one. And it is recommended for users to use. For more information about this method, please refer to [gatt_server_service_table_demo](../gatt_server_service_table).
+ESP-IDF also allows users to create a GATT service via an attribute table, rather than add attributes one by one. And it is recommended for users to use. For more information about this method, please refer to [gatt_server_service_table_demo](../../ble/gatt_server_service_table).
 
-To test this example, you can run the [gatt_client_demo](../gatt_client), which can scan for and connect to this example automatically, and run [gatt_server_demo](../gatt_server), Waiting to be connected. They will start exchanging data once the GATT client has enabled the notification function of the GATT server.
+To test this example, you can run the [gatt_client_demo](../../ble/gatt_client), which can scan for and connect to this example automatically, and run [gatt_server_demo](../../ble/gatt_server), Waiting to be connected. They will start exchanging data once the GATT client has enabled the notification function of the GATT server.
 
-Please check the [tutorial](tutorial/Gatt_Server_Example_Walkthrough.md) for more information about the gatts part of this example.
-Please check the [tutorial](tutorial/Gatt_Client_Example_Walkthrough.md) for more information about the gattc part of this example.
+Please check the [tutorial](../../ble/gatt_server/tutorial/Gatt_Server_Example_Walkthrough.md) for more information about the gatts part of this example.
+Please check the [tutorial](../../ble/gatt_client/tutorial/Gatt_Client_Example_Walkthrough.md) for more information about the gattc part of this example.
 

examples/bluetooth/esp_ble_mesh/README.md

@@ -1,6 +1,6 @@
 # ESP-BLE-MESH Examples
 
-[ESP-BLE-MESH]($IDF_PATH/components/bt/esp_ble_mesh/) is the official Bluetooth® Mesh stack of Espressif Systems. We will provide long-term support for new features, performance optimization, etc.
+[ESP-BLE-MESH](../../../components/bt/esp_ble_mesh/) is the official Bluetooth® Mesh stack of Espressif Systems. We will provide long-term support for new features, performance optimization, etc.
 
 Please help note that breaking changes may be introduced into ESP-BLE-MESH on [minor IDF versions](https://docs.espressif.com/projects/esp-idf/en/latest/versions.html).
 

examples/bluetooth/esp_ble_mesh/ble_mesh_wifi_coexist/README.md

@@ -17,4 +17,4 @@ WiFi的Iperf协议使用方法请参考[WiFi Iperf README](../../../wifi/iperf/R
 - Generic OnOff Server Model：此Model通过暴露自己的OnOff State，从而实现LED 灯的开关功能
 - Generic OnOff Client Model： 使用此Model可以实现开关功能，控制别的node 的LED灯的开关
 - Fast Provision Server Model： 此Model是为了进行快速配网而实现的自定义Model，通过此Model当节点作为临时provisioner进行配网成功后，需要将生成的Element地址通过此Model进行传给provisioner
-- Fast Provision Client Model：此Model和Fast Provision Server Model是配合使用的
+- Fast Provision Client Model：此Model和Fast Provision Server Model是配合使用的

examples/protocols/pppos_client/README.md

@@ -14,7 +14,7 @@ When PPP connection has been established, the IP packet flow from application si
 ### Hardware Required
 
 To run this example, you need an ESP32 dev board (e.g. ESP32-WROVER Kit) or ESP32 core board (e.g. ESP32-DevKitC).
-For test purpose, you also need a cellular modem module. Here we take the [SIM800L](http://www.simcom.com/product/showproduct.php?lang=en&id=277) and [BG96](https://www.quectel.com/product/bg96.htm) as an example.
+For test purpose, you also need a cellular modem module. Here we take the [SIM800L](https://www.simcom.com/product/SIM800.html) and [BG96](https://www.quectel.com/product/bg96.htm) as an example.
 You can also try other modules as long as they embedded PPP protocol.
 
 **Note:** Since SIM800L only support **2G** which will **not** work in some countries. And also keep in mind that in some other countries it will stop working soon (many remaining 2G networks will be switched off in the next 2-3 years). So you should **check with your local providers for further details** if you try this example with any 2G modules.

examples/system/app_trace_to_host/README.md

@@ -13,7 +13,7 @@ For more description of [logging to host](https://docs.espressif.com/projects/es
 
 Debugging of time critical functions may not work as desired if log messages are sent through the UART port. Printing out the logs may considerably slow down tested function to the point where it will not operate as expected.
 
-Let's consider a case we are testing implementation of [zero level crossing](https://en.wikipedia.org/wiki/Zero_crossing) detection for a 50 Hz signal with ESP32's ADC. 
+Let's consider a case we are testing implementation of [zero level crossing](https://en.wikipedia.org/wiki/Zero_crossing) detection for a 50 Hz signal with ESP32's ADC.
 
 We will start by checking if we can read ADC, what is the signal level and how many samples can be collected over 20 ms period by using a code snippet below:
 
@@ -36,7 +36,7 @@ I (4319) example: Sample:4, Value:27
 I (4319) example: Sample:5, Value:4095
 ```
 
-As you see we were able to collect only five samples. This seems rather not adequate for zero crossing detection. 
+As you see we were able to collect only five samples. This seems rather not adequate for zero crossing detection.
 
 We can remove `ESP_LOGI()` line and sample much faster, but then will not be able to see the values. To see the values we would need to save them in the memory and print out later.
 
@@ -46,7 +46,7 @@ Instead of saving samples to memory, a simple and compelling solution to this is
 esp_log_set_vprintf(esp_apptrace_vprintf);
 ```
 
-Once time critical messages are sent out, we can redirect `ESP_LOGx` back back to the UART by adding extra two lines of code. 
+Once time critical messages are sent out, we can redirect `ESP_LOGx` back back to the UART by adding extra two lines of code.
 
 ```c
 esp_log_set_vprintf(vprintf);
@@ -176,7 +176,7 @@ This is the log we have been looking for, complete with timestamps as if printed
 
 ## Example Output
 
-Check the full example code [app_trace_to_host](main/app_trace_to_host_test.c) that combines both tests above and runs them in a loop showing instantly the number of samples collected:
+Check the full example code [app_trace_to_host](main/app_trace_to_host_example_main.c) that combines both tests above and runs them in a loop showing instantly the number of samples collected:
 
 ```
 I (4289) example: Sampling ADC and sending data to the host...
@@ -199,7 +199,7 @@ With this example code we have demonstrated powerful functionality of logging to
 
 ## Troubleshooting
 1. I can not flash new firmware when OpenOCD is connected to ESP32.
-   * One likely cause would be that you set wrong SPI flash voltage when you start OpenOCD. Suppose you're working with an ESP32 board / module which has a 3.3V powered SPI flash, but you select 
+   * One likely cause would be that you set wrong SPI flash voltage when you start OpenOCD. Suppose you're working with an ESP32 board / module which has a 3.3V powered SPI flash, but you select
 `board/esp32-wrover.cfg` configuration file when start OpenOCD. In this situation, you might not be able to flash ESP32 when OpenOCD is connected. So make sure what the working voltage of the SPI flash is. Currently, for 1.8V flash, we'd like to suggest using `board/esp32-wrover.cfg` and for 3.3V flash, using `board/esp-wroom-32.cfg`. For more information about it, please refer to [ESP32 Modules and Boards](https://docs.espressif.com/projects/esp-idf/en/latest/hw-reference/modules-and-boards.html) and [Set SPI Flash Voltage](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/jtag-debugging/tips-and-quirks.html#why-to-set-spi-flash-voltage-in-openocd-configuration).
 
 (For any technical queries, please open an [issue](https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you as soon as possible.)

examples/system/ota/otatool/README.md

@@ -1,6 +1,6 @@
 # OTA Tool Example
 
-This example demonstrates common operations the OTA tool [otatool.py](../../../components/app_update/otatool.py) allows the user to perform:
+This example demonstrates common operations the OTA tool [otatool.py](../../../../components/app_update/otatool.py) allows the user to perform:
 
 - reading, writing and erasing OTA partitions,
 - switching boot partitions, and
@@ -44,7 +44,7 @@ Shell script:
 ./otatool_example.sh
 ```
 
-The script searches for valid target devices connected to the host and performs the operations on the first one it finds. This could present problems if there 
+The script searches for valid target devices connected to the host and performs the operations on the first one it finds. This could present problems if there
 are multiple viable target devices attached to the host. To perform the operations on a specific device, specify the port it is attached to during script invocation ("/dev/ttyUSB2" for example):
 
 Python script: