Upgrade Firmware Through a Local Host
In the ESP-IDF example, the procedure of OTA is shown in Figure 11.4.
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1. Enabling OTA server
Before running the OTA example, you need to first create the HTTPS
service and apply for a certificate. The certificate can be self-signed
by executing openssl req -x509 -newkey rsa:2048 -keyout ca_key.pem -out ca_cert.pem -days 365 -nodes
. Logs are as follows:
Generating a RSA private key
. +++++
....................+++++
writing new private key to 'ca_key.pem'
-----
You are about to be asked to enter information that will be incorporated into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.' , the field will be left blank.
-----
...
...
2. Enabling HTTPS service
The command openssl s_server -WWW -key ca_key.pem -cert ca_cert.pem -port 8070
will enable an HTTPS service with port 8070 on the local
machine. The logs are as follows:
...
Using default temp DH parameters
ACCEPT
...
...
Upon successful HTTPS connection, the logs are as follows:
139783954665920:error:14094416:SSL routines:ssl3_read_bytes:sslv3 alert
certificate unknown:../ssl/record/rec_layer_s3.c:1528:SSL alert number 46
FILE:advanced_https_ota.bin
...
...
3. Using the esp_https_ota
component to perform OTA
Before the OTA test, let's first look at how to write an OTA program. The following sample code comes from esp-idf/examples/system/ota/advanced_https_ota/main/advanced_https_ota_example.c
:
void app_main(void)
{
//Initialize NVS
esp_err_t err = nvs_flash_init();
if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
ESP_ERROR_CHECK(nvs_flash_erase());
err = nvs_flash_init();
}
ESP_ERROR_CHECK( err );
ESP_ERROR_CHECK(esp_netif_init());
ESP_ERROR_CHECK(esp_event_loop_create_default());
//Initialize connection
ESP_ERROR_CHECK(example_connect());
//firmware verification
const esp_partition_t *running = esp_ota_get_running_partition();
esp_ota_img_states_t ota_state;
if (esp_ota_get_state_partition(running, &ota_state) == ESP_OK) {
if (ota_state == ESP_OTA_IMG_PENDING_VERIFY) {
if (esp_ota_mark_app_valid_cancel_rollback() == ESP_OK) {
ESP_LOGI(TAG, "App is valid, rollback cancelled successfully");
} else {
ESP_LOGE(TAG, "Failed to cancel rollback");
}
}
}
#if CONFIG_EXAMPLE_CONNECT_WIFI
//Set PS mode
esp_wifi_set_ps(WIFI_PS_NONE);
#endif
//Create Over-the-air (OTA) task
xTaskCreate(&advanced_ota_example_task, "advanced_ota_example_task", 1024 * 8, NULL, 5, NULL);
}
The above code snippet demonstrates the following procedure:
-
Initialise NVS with the
nvs_flash_init()
function, which is generally the first step in writing an ESP32-C3 application. -
Initialise the
netif
layer and connect to Wi-Fi with theexample_connect()
function. This function is generic and is realised in theprotocol_examples_common
component. You can replace it with your own Wi-Fi connection function. -
If rollback is enabled, then you need to set the firmware status.
-
(Optional) Set the PS mode to
WIFI_PS_NONE
with theesp_wifi_set_ps()
function to disable the power saving mode and achieve maximum data throughput. -
Create an OTA task and complete the firmware receiving process in the task. For proceduce of
advanced_ota_example_task
, please refer to Section 11.1.3.
With the basic understanding of the above example, we can now proceed to the OTA test. Please perform and complete the following actions successively:
-
Set the target chip to ESP32-C3 with the following command:
$ idf.py set-target esp32c3
-
Set Wi-Fi information.
Run
idf.py menuconfig
and edit the Wi-Fi SSID and password as follows:(Top) → Example Connection Configuration Espressif IoT Development Framework Configuration [*] connect using WiFi interface (Xiaomi_32BD) WiFi SSID (12345678) WiFi Password [ ] connect using Ethernet interface [*] Obtain IPv6 address Preferred IPv6 Type (Local Link Address) --->
-
Set OTA information.
Fill in
Firmware Upgrade
URL and select skipping server certificate CN fieldcheck and firmware version check.(https://192.168.31.177:8070/advanced_https_ota.bin) Firmware Upgrade URL [*] Skip server certificate CN fieldcheck [*] Skip firmware version check (5000) OTA Receive Timeout
-
Build firmware with the command
idf.py build
.After building, extract
advanced_https_ota.bin
under thebuild
directory to the directory of the HTTPS server, namely, the directory where theopenssl s_server
operation is performed. -
Download firmware.
Run
idf.py flash monitor
to download the firmware and open monitor.Upon completion of all operations, ESP32-C3 will power up and connect to the set Wi-Fi and reboot after downloading the firmware from the set URL.