examples/console: add light sleep command

examples/system/console/main/console_example_main.c

@@ -68,6 +68,18 @@ static void initialize_console()
     /* Move the caret to the beginning of the next line on '\n' */
     esp_vfs_dev_uart_set_tx_line_endings(ESP_LINE_ENDINGS_CRLF);
 
+    /* Configure UART. Note that REF_TICK is used so that the baud rate remains
+     * correct while APB frequency is changing in light sleep mode.
+     */
+    const uart_config_t uart_config = {
+            .baud_rate = CONFIG_CONSOLE_UART_BAUDRATE,
+            .data_bits = UART_DATA_8_BITS,
+            .parity = UART_PARITY_DISABLE,
+            .stop_bits = UART_STOP_BITS_1,
+            .use_ref_tick = true
+    };
+    ESP_ERROR_CHECK( uart_param_config(CONFIG_CONSOLE_UART_NUM, &uart_config) );
+
     /* Install UART driver for interrupt-driven reads and writes */
     ESP_ERROR_CHECK( uart_driver_install(CONFIG_CONSOLE_UART_NUM,
             256, 0, 0, NULL, 0) );