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espressif_idf-extra-components/examples/peripherals/usb/host/cdc/common/cdc_acm_host
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Darian Leung ff8b939cbb usb: USB Host stack uses USB PHY driver 
This commit updates the USB Host stack to use the USB PHY driver. The
USB PHY and the OTG Controller should now both be setup/deleted using
usb_new_phy() and usb_del_phy() respectively.

- The hcd_install() now expects the USB PHY and OTG Contorller to be
    already setup before it is called
- usb_host_install() now has an option to skip calling usb_del_phy() if
    the user wants to setup their own USB PHY (e.g., in the case of using
    and external PHY).
- CDC-ACM and MSC examples/test updated to use internal PHY

Closes https://github.com/espressif/esp-idf/issues/8061
 		2022-07-12 08:15:33 +02:00
..
include/usb usb: Add USB host CDC-ACM class driver 2022-07-12 08:15:33 +02:00
test usb: USB Host stack uses USB PHY driver 2022-07-12 08:15:33 +02:00
CMakeLists.txt usb: Add USB host CDC-ACM class driver 2022-07-12 08:15:33 +02:00
README.md usb: Add USB host CDC-ACM class driver 2022-07-12 08:15:33 +02:00
cdc_acm_host.c usb: Add USB host CDC-ACM class driver 2022-07-12 08:15:33 +02:00

README.md

USB Host CDC-ACM Class Driver

This directory contains an implementation of a USB CDC-ACM Host Class Driver that is implemented on top of the USB Host Library.

Supported Devices

The CDC-ACM Host driver supports the following types of CDC devices:

  1. CDC-ACM devices
  2. CDC-like vendor specific devices (usually found on USB to UART bridge devices)

CDC-ACM Devices

The CDC-ACM Class driver supports CDC-ACM devices that meet the following requirements:

  • The device class code must be set to the CDC class 0x02 or implement Interface Association Descriptor (IAD)
  • The CDC-ACM must contain the following interfaces:
    • A Communication Class Interface containing a management element (EP0) and may also contain a notification element (an interrupt endpoint). The driver will check this interface for CDC Functional Descriptors.
    • A Data Class Interface with two BULK endpoints (IN and OUT). Other transfer types are not supported by the driver

CDC-Like Vendor Specific Devices

The CDC-ACM Class driver supports CDC-like devices that meet the following requirements:

  • The device class code must be set to the vendor specific class code 0xFF
  • The device needs to provide and interface containing the following endpoints:
    • (Mandatory) Two Bulk endpoints (IN and OUT) for data
    • (Optional) An interrupt endpoint (IN) for the notification element

For CDC-like devices, users are responsible for ensuring that they only call APIs (e.g., cdc_acm_host_send_break()) that are supported by the target device.

Usage

The following steps outline the typical API call pattern of the CDC-ACM Class Driver

  1. Install the USB Host Library via usb_host_install()
  2. Install the CDC-ACM driver via cdc_acm_host_install()
  3. Call cdc_acm_host_open()/cdc_acm_host_open_vendor_specific() to open a target CDC-ACM/CDC-like device. These functions will block until the target device is connected
  4. To transmit data, call cdc_acm_host_data_tx_blocking()
  5. When data is received, the driver will automatically run the receive data callback
  6. An opened device can be closed via cdc_acm_host_close()
  7. The CDC-ACM driver can be uninstalled via cdc_acm_host_uninstall()

Examples