USB-CDC串口资料资源-CSDN文库

共2个文件

pdf：1个

txt：1个

USB

SERIAL

需积分: 10 22 浏览量 2017-04-25 22:00:38 上传评论收藏 1.2MB RAR 举报

资源推荐

资源详情

资源评论

收起资源包目录

usb-cdc.rar （2个子文件）

AN00124--USB-CDC-Class-as-Virtual-Serial-Port_2.0.2rc1.pdf 1.34MB

参考网址.txt 46B

AN00124 (2.0.2)

Application Note: AN00124

USB CDC Class as Virtual Serial Port

This application note shows how to create a USB device compliant to the standard USB Communications

Device Class (CDC) on an XMOS multicore microcontroller.

The code associated with this application note provides an example of using the XMOS USB Device Library

(XUD) and associated USB class descriptors to provide a framework for the creation of a USB CDC device

that implements Abstract Control Model (ACM).

This example USB CDC ACM implementation provides a Virtual Serial port running over high speed USB.

The Virtual Serial port supports the standard requests associated with ACM model of the class.

A serial terminal program from host PC connects to virtual serial port and interacts with the application.

This basic application demo implements a loopback of characters from the terminal to the XMOS device

and back to the terminal. This application demo code demonstrates a simple way in which USB CDC class

devices can easily be deployed using an xCORE-USB device.

Note: This application note provides a standard USB CDC class device and as a result does not require

external drivers to run on Windows, Mac or Linux.

Required tools and libraries

• xTIMEcomposer Tools - Version 14.0.0

• XMOS USB library - Version 3.1.0

Required hardware

This application note is designed to run on an XMOS xCORE-USB series device.

The example code provided with the application has been implemented and tested on the xCORE-USB

sliceKIT (XK-SK-U16-ST) but there is no dependancy on this board and it can be modiﬁed to run on any

development board which uses an xCORE-USB series device.

Prerequisites

• This document assumes familiarity with the XMOS xCORE architecture, the Universal Serial Bus

2.0 Speciﬁcation and related speciﬁcations, the XMOS tool chain and the xC language. Docu-

mentation related to these aspects which are not speciﬁc to this application note are linked to

in the references appendix.

• For descriptions of XMOS related terms found in this document please see the XMOS Glossary

• For the full API listing of the XMOS USB Device (XUD) Library please see the document XMOS USB

Device (XUD) Library

• For information on designing USB devices using the XUD library please see the XMOS USB Device

Design Guide for reference

http://www.xmos.com/published/glossary

http://www.xmos.com/published/xuddg

http://www.xmos.com/published/xmos-usb-device-design-guide

XM006845

AN00124 (2.0.2)

1 Overview

1.1 Introduction

USB Communication Class is a composite USB device class that enables telecommunication devices like

digital telephones, ISDN terminal adapters, etc and networking devices like ADSL modems, Ethernet

adapters/hubs, etc to connect to a USB host machine. It speciﬁes multiple models to support diﬀerent

types of communication devices. Abstract Control Model (ACM) is deﬁned to support legacy modem de-

vices and an advantage of ACM is the Serial emulation feature. Serial emulation of a USB device eases the

development of host PC application, provides software compatibility with RS-232 based legacy devices,

enables USB to RS-232 conversions and gives good abstraction over the USB for application developers.

In this application note, the USB CDC implementation on xCORE-USB device is explained in detail which

will help you in two ways. First, it acts as reference for you to build your own USB CDC class device,

second, it gives you an idea of how to use this virtual serial port code in your application.

The standard USB CDC class speciﬁcation can be found in the USB-IF website.

(http://www.usb.org/developers/docs/devclass_docs/CDC1.2_WMC1.1_012011.zip)

1.2 Block diagram

Modem

Speaker

Phone

USB to RS-232

Converter

USB CDC compliant

Vendor Device

XMOS

XS1-U6A-64

XMOS

XS1-U6A-64

XMOS

XS1-U6A-64

XMOS

XS1-U6A-64

XMOS

XS1-U6A-64

XMOS

XS1-U6A-64

XMOS

XS1-U6A-64

XMOS

XS1-U6A-64

Figure 1: Block diagram of USB CDC applications

XM006845

AN00124 (2.0.2)

2 USB CDC Class application note

The example in this application note uses the XMOS USB device library and shows a simple program

that enumerates a USB CDC Class device as virtual serial port in a host machine and provides a simple

character loopback device.

For this USB CDC device application example, the system comprises four tasks running on separate logical

cores of an xCORE-USB multicore microcontroller.

The tasks perform the following operations.

• A task containing the USB library functionality to communicate over USB.

• A task implementing Endpoint0 responding to both standard and CDC class-speciﬁc USB requests.

• A task implementing the data endpoints and notiﬁcation endpoint of the CDC ACM class. It handles

tx and rx buﬀers and provides interface for applications.

• A task implementing the application logic to interact with user over the virtual serial port.

These tasks communicate via the use of xCONNECT channels which allow data to be passed between ap-

plication code running on separate logical cores. In this example, XC interfaces are used, which abstracts

out the channel communication details with function level interface.

The following diagram shows the task and communication structure for this USB CDC class application

example.

Virtual COM

Applicaiton

Virtual COM

Applicaiton

XUD

Manager

XUD

Manager

XS1-U8A-64

USB

PHY

Endpoint 0

Handler

Endpoint 0

Handler

CDC

Endpoints

Handler

CDC

Endpoints

Handler

c_ep_out[0]

c_ep_in[0]

c_ep_out[1]

c_ep_in[1]

c_ep_in[2]

usb_cdc_interface

I/O

Figure 2: Task diagram of the USB CDC Virtual Serial Port example

XM006845

AN00124 (2.0.2)

2.1 Makeﬁle additions for this example

To start using the USB library, you need to add lib_usb to your makeﬁle:

USED_MODULES = ... lib_usb ...

You can then access the USB functions in your source code via the usb.h header ﬁle:

#include <usb.h>

2.2 Source code ﬁles

The example application consists of the following ﬁles:

main.xc

xud_cdc.xc

xud_cdc.h

xud_cdc.xc contains the CDC ACM implementation which includes the USB descriptors, endpoints handler

functions and the xC interface (APIs) for application programs. The xud_cdc.h header is included in

the main.xc to use the APIs exposed by xud_cdc.xc. The main.xc implements the application logic that

interacts over the USB CDC link with a host terminal application.

2.3 Declaring resource and setting up the USB components

main.xc contains the application implementation for a device based on the USB CDC device class. There

are some deﬁnes in it that are used to conﬁgure the XMOS USB device library. These are displayed below.

USB Endpoint Defines

#define XUD_EP_COUNT_OUT 2 //Includes EP0 (1 OUT EP0 + 1 BULK OUT EP)

#define XUD_EP_COUNT_IN 3 //Includes EP0 (1 IN EP0 + 1 INTERRUPT IN EP + 1 BULK IN EP)

These deﬁnes describe the endpoints conﬁguration for this device. This example has bi-directional com-

munication with the host machine via the standard endpoint0 and three other endpoints for implementing

the part of our CDC class device.

These deﬁnes are passed to the setup function for the USB library which is called from main().

2.4 The application main() function

Below is the source code for the main function of this application, which is taken from the source ﬁle

main.xc

XM006845

AN00124 (2.0.2)

int main() {

Channels to communicate with USB endpoints

chan c_ep_out[XUD_EP_COUNT_OUT], c_ep_in[XUD_EP_COUNT_IN];

Interface to communicate with USB CDC (Virtual Serial)

interface usb_cdc_interface cdc_data;

par

{

on USB_TILE: xud(c_ep_out, XUD_EP_COUNT_OUT, c_ep_in, XUD_EP_COUNT_IN,

null, XUD_SPEED_HS, XUD_PWR_SELF);

on USB_TILE: Endpoint0(c_ep_out[0], c_ep_in[0]);

on USB_TILE: CdcEndpointsHandler(c_ep_in[1], c_ep_out[1], c_ep_in[2], cdc_data);

on tile[1]: app_virtual_com(cdc_data);

}

return 0;

}

Looking at this in a more detail you can see the following:

• The par statement starts four separate tasks in parallel.

• There is a task to conﬁgure and execute the USB library: xud. This library call runs in an inﬁnite

loop and handles all the underlying USB communications and provides abstraction at the endpoints

level.

• There is a task to startup and run the Endpoint0 code: Endpoint0(). It handles the control endpoint

zero and must be run in a separate logical core inorder to promptly respond to the control requests

from host.

• There is a task to handle all the other three endpoints required for the CDC class:

CdcEnpointsHandler(). This function handles one bulk OUT and one bulk IN endpoints for data

transmissions and one interrupt IN endpoint for sending notiﬁcations to host.

• There is a task to run the application logic that interacts with user over the virtual serial port:

app_virtual_com().

• The deﬁne USB_TILE describes the tile on which the individual tasks will run.

• The xCONNECT communication channels and the xC interface cdc_data used for inter task commu-

nication are setup at the beginning of main() and passed on to respective tasks.

• The USB deﬁnes discussed earlier are passed into the function xud().

2.5 Conﬁguring the USB Device ID

The USB ID values used for vendor ID, product ID and device version number are deﬁned in the ﬁle

xud_cdc.xc. These are used by the host machine to determine the vendor of the device (in this case

XMOS) and the product plus the ﬁrmware version.

USB CDC device product defines

#define BCD_DEVICE 0x0100

#define VENDOR_ID 0x20B1

#define PRODUCT_ID 0x0401

XM006845

评论收藏

内容反馈

kz2

粉丝: 7
资源: 38

USB-CDC串口资料

USB CDC串口

usb-cdc协议

USB CDC COM.zip

usb cdc 标准协议文档

USB_CDCV1.2协议

USB CDC 标准协议v1.1&v1;.2大全.rar

USB CDC 转串口测试说明

STM32F407VG USB_CDC虚拟串口

基于Qt实现USB CDC便携式设备串口通信客户端设计

实验48 USB虚拟串口实验_CDC_usb_虚拟串口_

STM32F407-HAL库：USB实验（CDC虚拟串口）- 程序源码

android-Usb-cdc.apk

USB Host 驱动CDC设备超详细资料-原创

ALIENTEK MiniSTM32-STM32F103RC-USB-CDC-VPC

USB CDC C源码

STM32F407 USB通信程序 USB Device 虚拟串口 CDC类 Cubemx生成

USB CDC串口 扫码枪 浏览器插件-龙芯+中标麒麟系统

stm32 USB HID+CDC 鼠标键盘串口 组合设备配置解析

Linux的USB虚拟串口驱动（CDC-ACM驱动）源码

ST USB Composite 复合设备 虚拟串口 CDC 驱动无法安装解决办法

USB CDC DRIVER.rar

usbcdc类实例，usb转虚拟串口

STM32F4 USB-FS 枚举为复合设备 MSC+CDC

LPC1768-USB-Disk-dev-src

STM32G474实现USB的MSC+CDC的组合功能

STM32CubeMX学习笔记-USB接口使用（CDC虚拟串口）

STC8-USBCDC模拟串口收发数据

STM32F469 重定向printf到USB CDC

Win7_Usb_cdc驱动安装.zip

最新资源

USB CDC串口扫码枪浏览器插件-龙芯+中标麒麟系统

stm32 USB HID+CDC 鼠标键盘串口组合设备配置解析

ST USB Composite 复合设备虚拟串口 CDC 驱动无法安装解决办法