USBCDC_ECM
USBCDC_ECM class hierarchy
The USBCDC_ECM class emulates an Ethernet interface over USB. You can use the interface to send and receive Ethernet frames over USB.
One application in which you can use this class is a USB to Ethernet adapter. If you add an IP stack and web server on top of this class, you can also create a USB web server that allows you to configure a USB device and to view data using a web browser.
USBCDC_ECM class reference
| Public Member Functions | |
| USBCDC_ECM (bool connect_blocking=true, uint16_t vendor_id=0x0700, uint16_t product_id=0x0101, uint16_t product_release=0x0001) | |
| Basic constructor. More... | |
| USBCDC_ECM (USBPhy *phy, uint16_t vendor_id, uint16_t product_id, uint16_t product_release) | |
| Fully featured constructor. More... | |
| virtual | ~USBCDC_ECM () |
| Destroy this object. More... | |
| bool | ready () |
| Check if this class is ready. More... | |
| void | wait_ready () |
| Block until this device is configured. More... | |
| bool | send (uint8_t *buffer, uint32_t size) |
| Send a buffer. More... | |
| void | receive_nb (uint8_t *buffer, uint32_t size, uint32_t *actual) |
| Read from the receive buffer. More... | |
| uint16_t | read_packet_filter () |
| Return ethernet packet filter bitmap. More... | |
| void | attach_rx (mbed::Callback< void()> cb) |
| Attach a callback for when an ethernet packet is received. More... | |
| void | attach_filter (mbed::Callback< void()> cb) |
| Attach a callback for when a request to configure device ethernet packet filter is received. More... | |
| void | init () |
| Initialize this instance. More... | |
| void | deinit () |
| Power down this instance. More... | |
| bool | configured () |
| Check if the device is configured. More... | |
| void | connect () |
| Connect a device This method can also be used to resume USB operation when USB power is detected after it was suspended via USBDevice::deinit. More... | |
| void | disconnect () |
| Disconnect a device. More... | |
| void | sof_enable () |
| Enable the start of frame interrupt. More... | |
| void | sof_disable () |
| Disable the start of frame interrupt. More... | |
| bool | endpoint_add (usb_ep_t endpoint, uint32_t max_packet, usb_ep_type_t type, mbed::Callback< void()> callback=nullptr) |
| Add an endpoint. More... | |
| template<typename T > | |
| bool | endpoint_add (usb_ep_t endpoint, uint32_t max_packet, usb_ep_type_t type, void(T::*callback)()) |
| Add an endpoint. More... | |
| void | endpoint_remove (usb_ep_t endpoint) |
| Remove an endpoint. More... | |
| void | endpoint_remove_all () |
| Remove all non-zero endpoints. More... | |
| void | endpoint_stall (usb_ep_t endpoint) |
| Stall an endpoint. More... | |
| void | endpoint_unstall (usb_ep_t endpoint) |
| Un-stall an endpoint. More... | |
| uint32_t | endpoint_max_packet_size (usb_ep_t endpoint) |
| Get the current maximum size for this endpoint. More... | |
| void | endpoint_abort (usb_ep_t endpoint) |
| Abort the current transfer on this endpoint. More... | |
| bool | read_start (usb_ep_t endpoint, uint8_t *buffer, uint32_t size) |
| start a read on the given endpoint More... | |
| uint32_t | read_finish (usb_ep_t endpoint) |
| Get the status of a read. More... | |
| bool | write_start (usb_ep_t endpoint, uint8_t *buffer, uint32_t size) |
| Write a data to the given endpoint. More... | |
| uint32_t | write_finish (usb_ep_t endpoint) |
| Get the status of a write. More... | |
| Protected Member Functions | |
| virtual void | callback_state_change (DeviceState new_state) |
| Called when USB changes state. More... | |
| virtual void | callback_request_xfer_done (const setup_packet_t *setup, bool aborted) |
| Called by USBDevice on data stage completion. More... | |
| virtual void | callback_request (const setup_packet_t *setup) |
| Called by USBDevice on Endpoint0 request. More... | |
| virtual void | callback_reset () |
| Called by USBDevice layer on bus reset. More... | |
| virtual void | callback_power (bool powered) |
| Called by USBDevice layer on power state change. More... | |
| virtual void | callback_sof (int frame_number) |
| Called by USBDevice layer on each new USB frame. More... | |
| void | complete_request (RequestResult result, uint8_t *data=NULL, uint32_t size=0) |
| Called to complete the setup stage of a callback request. More... | |
| void | complete_request_xfer_done (bool success) |
| Called to complete the data stage of a callback request. More... | |
| void | complete_set_configuration (bool success) |
| Called to complete a set configuration command. More... | |
| void | complete_set_interface (bool success) |
| Called to complete a set interface command. More... | |
| uint8_t * | find_descriptor (uint8_t descriptor_type, uint8_t index=0) |
| Find a descriptor type inside the configuration descriptor. More... | |
| const usb_ep_table_t * | endpoint_table () |
| Get the endpoint table of this device. More... | |
| virtual void | start_process () |
| Callback called to indicate the USB processing needs to be done. More... | |
| virtual void | lock () |
| Acquire exclusive access to this instance USBDevice. More... | |
| virtual void | unlock () |
| Release exclusive access to this instance USBDevice. More... | |
| virtual void | assert_locked () |
| Assert that the current thread of execution holds the lock. More... | |
Note: Because Windows doesn’t provide native support for the USB CDC-ECM model, you must use third party drivers to use this class on Windows.
USBCDC_ECM example
The example below sends an Ethernet frame that carries "Hello world" payload with a custom EtherType to the host PC. You can capture the frame by using a program called "Wireshark":
- Flash the board, and ensure the target's USB is plugged into the PC.
- Open Wireshark.
- Click Capture > Options to select the correct capture interface.
- Click Capture > Start.
- Click captured packet from source address 12:34:56:78:9a:bc to see the "Hello world" payload.
/*
* Copyright (c) 2006-2020 Arm Limited and affiliates.
* SPDX-License-Identifier: Apache-2.0
*/
#include "mbed.h"
#include "USBCDC_ECM.h"
/* Ethernet II frame */
typedef struct {
uint8_t dst_mac[6];
uint8_t src_mac[6];
uint16_t eth_type;
char payload[12];
} packet_t;
static packet_t packet = {
.dst_mac = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
.src_mac = {0x12, 0x34, 0x56, 0x78, 0x9a, 0xbc},
.eth_type = 0xaaaa, /* unused EtherType */
.payload = "Hello world"
};
USBCDC_ECM ecm;
int main()
{
// Let the USB device to setup
ThisThread::sleep_for(10);
// Send "Hello world" packets in loop
while (true) {
ecm.send((uint8_t *)&packet, sizeof(packet));
ThisThread::sleep_for(1000);
}
}