The driver allows you to use {IDF_TARGET_NAME} chips to develop USB devices on a top of TinyUSB stack. TinyUSB is integrated with ESP-IDF to provide USB features of the framework. Using this driver the chip works as simple or composite device supporting several USB devices simultaneously.
Our USB-OTG implementation is limited to {IDF_TARGET_USB_EP_NUM} USB endpoints ({IDF_TARGET_USB_EP_NUM_INOUT} IN/OUT endpoints and {IDF_TARGET_USB_EP_NUM_IN} IN endpoint) . Please note that enabling Secure Boot or flash encryption disables the USB-OTG USB stack in the ROM, disallowing updates via the serial emulation or Device Firmware Update (DFU) on that port. For more details, please refer to `technical reference manual <{IDF_TARGET_TRM_EN_URL}>`_.
The driver's descriptors are provided by :cpp:type:`tinyusb_config_t` structure's :cpp:member:`device_descriptor`, :cpp:member:`configuration_descriptor` and :cpp:member:`string_descriptor` members. Therefore, you should initialize :cpp:type:`tinyusb_config_t` with your desired descriptors before calling :cpp:func:`tinyusb_driver_install` to install the driver.
However, the driver also provides default descriptors. You can install the driver with default device and string descriptors by setting the :cpp:member:`device_descriptor` and :cpp:member:`string_descriptor` members of :cpp:type:`tinyusb_config_t` to `NULL` before calling :cpp:func:`tinyusb_driver_install`. To lower your development effort we also provide default configuration descriptor for CDC and MSC class, as these classes rarely require custom configuration. The driver's default device descriptor is specified using Menuconfig, where the following fields should be configured:
To initialize the driver, users should call :cpp:func:`tinyusb_driver_install`. The driver's configuration is specified in a :cpp:type:`tinyusb_config_t` structure that is passed as an argument to :cpp:func:`tinyusb_driver_install`.
Note that the :cpp:type:`tinyusb_config_t` structure can be zero initialized (e.g. ``const tinyusb_config_t tusb_cfg = { 0 };``) or partially (as shown below). For any member that is initialized to `0` or `NULL`, the driver will use its default configuration values for that member (see example below)
USB specification mandates self-powered devices to monitor voltage level on USB's VBUS signal. As opposed to bus-powered devices, a self-powered device can be fully functional even without USB connection. The self-powered device detects connection and disconnection events by monitoring the VBUS voltage level. VBUS is considered valid if it rises above 4.75 V and invalid if it falls below 4.35 V.
No {IDF_TARGET_NAME} pin is 5 V tolerant, so you must connect the VBUS to {IDF_TARGET_NAME} via a comparator with voltage thresholds as described above, or use a simple resistor voltage divider that will output (0.75 x Vdd) if VBUS is 4.4 V (see figure below). In both cases, voltage on the sensing pin must be logic low within 3 ms after the device is unplugged from USB host.
To use this feature, in :cpp:type:`tinyusb_config_t` you must set :cpp:member:`self_powered` to ``true`` and :cpp:member:`vbus_monitor_io` to GPIO number that will be used for VBUS monitoring.
If the CDC option is enabled in Menuconfig, the USB Serial Device can be initialized with :cpp:func:`tusb_cdc_acm_init` according to the settings from :cpp:type:`tinyusb_config_cdcacm_t` (see example below).
To specify callbacks you can either set the pointer to your :cpp:type:`tusb_cdcacm_callback_t` function in the configuration structure or call :cpp:func:`tinyusb_cdcacm_register_callback` after initialization.
The driver allows to redirect all standard application streams (stdin, stdout, stderr) to the USB Serial Device and return them to UART using :cpp:func:`esp_tusb_init_console`/:cpp:func:`esp_tusb_deinit_console` functions.
If the MSC CONFIG_TINYUSB_MSC_ENABLED option is enabled in Menuconfig, the ESP Chip can be used as USB MSC Device. The storage media (spi-flash or sd-card) can be initialized as shown below (see example below).
