参数资料
| 型号： | DM163010 |
| 厂商： | Microchip Technology |
| 文件页数： | 29/80页 |
| 文件大小： | 0K |
| 描述： | BOARD DEMO PICDEM USB |
| 标准包装： | 1 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页当前第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页
USB Demonstration Code
There is no way to tell what endpoint a report descriptor is associated with by
looking at the report descriptor. In other words, unlike other descriptor types,
report descriptors do not have a field that identifies them as a report descrip-
tor. Nor do report descriptors have an index number that distinguishes one
from another. Report descriptors are associated with the appropriate endpoint
in the firmware with the use of a Report Descriptor Index.
Looking at Figure 2.5 again, you can see that HID1 is associated with
endpoint1 and that HID1 specifies that it has a report descriptor. The host
assigns this report descriptor an index value of 0 (this is a zero based array),
simply because the HID1 descriptor is the first descriptor sent to the host that
specifies a report descriptor. Similarly, the host assigns the report descriptor
specified by HID2 an index value of 1. The host keeps track of what descrip-
tors branch off a particular interface, therefore, the host is able to deduce that
report descriptors with indexes 0 and 1 are describing the communication that
will take place over endpoint1 and endpoint2, respectively. The host will call
these report descriptors with the Get_Report_Descriptor request. As part of
this request, the host specifies the index number of the descriptor it desires.
It's up to the developer to make sure that Report Descriptor 1 is sent to the
host when index 0 is specified in the request, and Report Descriptor 2 is sent
to the host when index 1 is specified. To make this process as painless as
possible, the Report Descriptor Index in file descript.asm was created. In
this index, all that is needed, is for you to list the labels of your report descrip-
tors in the order that the corresponding HID descriptors are sent to the host.
2.4
Multi-Function LCD Text Display Example
2.4.1
2.4.2
2001 Microchip Technology Inc.
Introduction
USB endpoints can be used to send data from the host as well as receive
data from a device. In this example, a simple vendor defined protocol is used
to draw text on the LCD. Additional commands are provided to move the cur-
sor around, clear the screen, download custom font characters, send data
through the serial port, and light LED’s on PORTB. This example does not
use the alphanumeric HID class defined by the USB-IF. This example used
the second endpoint to provide additional functionality. The second endpoint
will receive serial data from the UART and read the analog-to-digital
converter.
Hardware Implementation
The hardware is simply the PICDEM? USB with an LCD character module
attached to the LCD connector. The LCD control signals are PORTE, while the
data is PORTD. Provision is in place for backlight power on the PICDEM?
USB, but backlight control is not provided. If you use an LCD with an LED
backlight, your board could draw slightly more than 100 mA. Fortunately, cur-
rent PC drivers will not shut-down the device for using too much current,
unless the current draw from all the USB ports or a hub exceeds 500 mA.
Future PC drivers may require additional power management capabilities.
DS41174A-page 25
相关PDF资料 |
PDF描述 |
|---|---|
| DM163012 | BOARD DEMO PICDEM FOR 16C781/782 |
| DM163024 | BOARD DEMO PICDEM.NET 2 |
| DM163025 | PIC DEM FULL SPEED USB DEMO BRD |
| DM163028 | BOARD DEMO PICDEM LCD |
| DM163029 | BOARD PICDEM FOR MECHATRONICS |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DM163010 | 制造商:Microchip Technology Inc 功能描述:DEMONSTRATION BOARD ((NW)) |
| DM163011 | 功能描述:开发板和工具包 - PIC / DSPIC For PIC18FXX8 RoHS:否 制造商:Microchip Technology 产品:Starter Kits 工具用于评估:chipKIT 核心:Uno32 接口类型: 工作电源电压: |
| DM163011 | 制造商:Microchip Technology Inc 功能描述:DEVELPMENT TOOLS ((NW)) |
| DM163012 | 功能描述:开发板和工具包 - PIC / DSPIC For PIC16C781/782 RoHS:否 制造商:Microchip Technology 产品:Starter Kits 工具用于评估:chipKIT 核心:Uno32 接口类型: 工作电源电压: |
| DM163014 | 功能描述:开发板和工具包 - PIC / DSPIC PICDEM 4 RoHS:否 制造商:Microchip Technology 产品:Starter Kits 工具用于评估:chipKIT 核心:Uno32 接口类型: 工作电源电压: |
发布紧急采购，3分钟左右您将得到回复。