Communicating with Human Interface Devices such as Alphanumeric display, Bar Code Reader, Sensors, Volume control on Speakers/Headsets becomes a primary use case for real-world applications. Do you spend more time in building libraries to communicate with HID for your Delphi/C++ and Lazarus Applications? WINSOFT Provides a powerful library to get the job done. It uses the standard Windows HID API.
- Able to notify on HID Device arrival and removal.
- Can retrieve all the HID devices information available in the System.
- Flexible to getting/set Feature Report for the HID devices.
- Works with Windows 32/64-bit applications.
Versions Supported: Delphi/C++ Builder 5 – Delphi 10.4 and Lazarus 2.0.8.
Steps to Download and use the Native HID Library:
- Download Native HID and Unzip the file.
- Navigate to the Library folder for different Versions. e.g) Delphi10.4.
- Read the Readme.txt file to know about features and copyright information.
- Create a Windows VCL Application and use Hid.pas in the uses section.
- Include the Library folder into Project->Options->Delphi Compiler->Search Path.
- Compile and check for using the library.
NativeHID Download and Use demo:
Key HID concepts:
Report -Reports are the actual data that is exchanged between a device and a software client.
- Input Report – Data sent from the HID device to the application, typically when the state of a control changes.
- Output Report – Data sent from the application to the HID device, for example to the LEDs on a keyboard.
- Feature Report -Data that can be manually read and/or written, and are typically related to configuration information.
Report Descriptor – The Report Descriptor describes the format and meaning of the data that the device supports.
UsageTables – Contain a list with descriptions of Usages, which describe the intended meaning and use of a particular item described in the Report Descriptor. For example, a Usage is defined for the left button of a mouse. USB-IF WorkGroup Publishes the Usage Tables. See USB-IF HID Specifications.
How to build applications using Native HID library:
1. Open Rad Studio 10.4 and Create a Windows VCL Application, use Hid.pas in the uses section.
2. Include the Library folder into Project->Options->Delphi Compiler->Search Path.
3. Device := THidDevice.Create; // Creates an Instance of THidDevice
- OnDeviceArrival– Provide the DeviceName which arrives at the system. Using DeviceName you can open the device, show the device properties.
- OnDeviceRemoved – Provide the DeviceName which removed from the system.
- Get/SetFeatureReport – Use this to manually Read/Write Related to configuration information.
- GetInputReport – Get the data sent by HID Device for the Report ID.
- SetOutputReport – Set the data to HID Device for the Report ID.
4. Device.Open // Open the HID Device.
5. ShowDeviceProperties. with Device do try AddLine('Vendor ID: ' + IntToHex(VendorID,4)); AddLine('Product ID: ' + IntToHex(ProductID,4)); AddLine('Version Number: ' + IntToHex(VersionNumber,4)); AddLine('Serial Number: ' + SerialNumber); AddLine('Manufacturer: ' + Manufacturer ); AddLine('Product: ' + Product); AddLine('Usage Page: ' + IntToStr(UsagePage)); AddLine('Usage: ' + IntToStr(Usage)); AddLine('Input Report length: ' + IntToStr(InputReportLength)); AddLine('Output Report Length: ' + IntToStr(OutputReportLength)); AddLine('Feature Report Length : ' + IntToStr(FeatureReportLength)); AddLine('Input Buffer Count : ' + IntToStr(InputBufferCount)); for I := 1 to 255 do if HasString[I] then AddLine('String ' + IntToStr(I) + ':' + Strings[I]) else Break; except on E: Exception do AddLine('Exception: ' + E.Message); end;
6. Get Device Names, var DeviceNames : TWStringDynArray; begin With Device do DeviceNames := Enumerate; end;
7.For each DeviceNames GetFeatureReport With Device do if FeatureReportSupported then for J := 0 to 9 do try AddLine('Feature report' + IntToStr(J) + ':' + ByteArrayToString(GetFeatureReport(J))); except On E: Exception do AddLine('Feature Report' + IntToStr(J) + 'Exception : ' + E.Message); end;
8. For each DeviceNames GetInputReport : if InputReportSupported then for J := 0 to 9 do try AddLine('Input report' + IntToStr(J) + ':' + ByteArrayToString(GetInputReport(J))); except On E: Exception do AddLine('Input Report' + IntToStr(J) + 'Exception : ' + E.Message); end;
9. For each DeviceNames Read by reopening the Device in Read only: With Device do if ReadSupported then begin if active then Close; Open(DeviceNames[I],True,False); for J := 0 to 9 do try AddLine('Read' + ByteArrayToString(Read(300))); except On E: Exception do AddLine('Read exception' + E.Message); end; end;
10. Device.close; // close the HID Device.
Native HID Library Code demo :
Conclusion: It’s quite easy to interact with HID in your applications. WINSOFT saved our time in nailing the Windows HID API and helped us to build quickly using the NativeHID Library.
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