1# Introduction to Driver Development Kit 2 3Empowered by the C-API solution, Driver Development Kit provides easy-to-use, secure, and diversified ArkTs-API and C APIs to elevate your experience in developing peripheral drivers, which bring ultimate plug-and-play experience to users. 4 5## When to Use 6 7With Driver Development Kit, you can develop dedicated or extended peripheral drivers in an efficient and secure manner. 8 91. Develop drivers of dedicated 10 11 peripherals for bank counters, enterprise office, and medical detection, such as high-speed document scanners, ID card scanners, fingerprint scanners, and blood oxygen and blood glucose meters. 12 132. Develop enhanced functions of non-standard peripherals, 14 15 such as customizing handwriting pad shortcut keys, setting the pressure sensing/drawing area, setting extended enhancement capabilities, setting the mouse lighting effect, customizing mouse extended buttons, and setting DPI and X and Y axes. 16 17## Typical Use Cases 18 19- You can develop advanced peripheral functions to meet user requirements. 20 21- The extended driver framework supports lifecycle management of peripheral drivers and provides APIs for querying and binding peripheral devices. 22 23## Basic Concepts 24 25- Peripheral driver client: [basic UI-based driver](externaldevice-guidelines.md), which is used to query and bind drivers, and customize the communication mode and data processing mode. 26- Peripheral driver: [basic UI-free driver](driverextensionability.md), which is the dedicated peripheral driver or enhanced peripheral driver developed based on the DDK. 27- External Device Manager: performs lifecycle management of peripheral devices and driver packages. 28- Bundle Manager Service (BMS): manages application installation, uninstallation, and data on the system. 29- Ability Manager Service (AMS): starts and stops **DriverExtensionAbility**. 30 31## Implementation Principles 32 33The HDF extended driver framework provides unified APIs for you to leverage the DDK capabilities for user-mode peripheral driver development. 34 35External Device Manager, the core service of user-mode peripheral management, performs lifecycle management of peripherals and peripheral drivers. In addition, standard ArkTS APIs are provided to query, bind, and unbind peripherals. 36 37### Peripheral Driver Architecture 38 39 **Figure 1** Peripheral driver working mechanism 40 41 42 43 44### Operation Process 45 46Figure 2 shows the process for matching a peripheral driver client with a peripheral driver when a peripheral is connected. 47 48**Figure 2** Process for matching a peripheral driver client with a peripheral driver 49 50 51 52Figure 3 shows the process for binding the peripheral driver client with a peripheral driver. 53 54**Figure 3** Process of binding the peripheral driver client with a peripheral driver 55 56 57 58## Notes and Constraints 59 60To call the ArkTs or C APIs provided by Driver Development Kit, you need to apply for specified permissions. 61 62The following table lists the required permissions. 63 64| API Type| DDK Type| Permission| 65| --------- | --------- | --------- | 66| ArkTs-API | NA| ohos.permission.ACCESS_EXTENSIONAL_DEVICE_DRIVER | 67| C-API | USB DDK | ohos.permission.ACCESS_DDK_USB | 68| C-API | HID DDK | ohos.permission.ACCESS_DDK_HID | 69| C-API | USB Serial DDK | ohos.permission.ACCESS_DDK_USB_SERIAL | 70| C-API | SCSI Peripheral DDK | ohos.permission.ACCESS_DDK_SCSI_PERIPHERAL | 71 72## Associated Modules 73 74The following table lists the associated modules you may use during development of peripheral drivers. 75 76| Name| Description| 77| --------- | --------- | 78| PerformanceAnalysisKit | Introduces {hilog} for log printing.| 79| BasicServicesKit | Introduces {BusinessError} to capture error information.| 80| IPCKit | Introduces {rpc} to implement inter-process communication between the driver and the client.| 81| AbilityKit | Introduces {want} for lifecycle management.| 82
