In this document
Multi-track recording With four XLR/TRS combo inputs, a 3.5mm stereo input, and a Zoom mic capsule input, the F4 can record up to six discrete tracks with an additional stereo mix track—all at resolutions up to 24-bit/192 kHz. Camera return Input 5/6 can be used as a camera return for monitoring only. This allows you to monitor audio being. The input device does not have any gamepad buttons. This condition resolves an ambiguity with certain gamepads that report axes with codes that overlaps those of the MT axes. An input device is classified as a single-touch device if both of the following conditions hold: The input device is not classified as a multi-touch device.
- Get your product drivers, manuals, and warranty information. Or just go here to download the latest driver. Pen input device for a computer.
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This section describes how the display driver functions and offers a functional template designed to help you build your own device-specific driver.
Android relies on the standard frame buffer device (
/dev/graphics/fb0) and driver as described in the
linux/fb.h kernel header file. For more information regarding the standard Linux frame buffer, please see The Frame Buffer Device at http://kernel.org.
In Android, every window gets implemented with an underlying Surface object, an object that gets placed on the framebuffer by SurfaceFlinger, the system-wide screen composer. Each Surface is double-buffered. The back buffer is where drawing takes place and the front buffer is used for composition.
unlockCanvas() is called, the back buffer is posted, which means that it gets displayed and becomes available again. Android flips the front and back buffers, ensuring a minimal amount of buffer copying and that there is always a buffer for SurfaceFlinger to use for composition (which ensures that the screen never flickers or shows artifacts).
Android makes two requirements of the driver: a linear address space of mappable memory that it can write to directly and support for the rgb_565 pixel format. A typical frame display includes:
- accessing the driver by calling open on
- using the
FBIOGET_VSCREENINFOInput / Output Control (ioctl) calls to retrieve information about the screen
FBIOPUT_VSCREENINFOioctl to attempt to create a virtual display twice the size of the physical screen and to set the pixel format to rgb_565. If this succeeds, double buffering is accomplished with video memory.
When a page flip is required, Android makes another
FBIOPUT_VSCREENINFO ioctl call with a new y-offset pointing to the other buffer in video memory. This ioctl, in turn, invokes the driver's
.fb_pan_display function in order to do the actual flip. If there isn't sufficient video memory, regular memory is used and is just copied into the video memory when it is time do the flip. After allocating the video memory and setting the pixel format, Android uses
mmap() to map the memory into the process's address space. All writes to the frame buffer are done through this mmaped memory.
To maintain adequate performance, framebuffer memory should be cacheable. If you use write-back, flush the cache before the frame buffer is written from DMA to the LCD. If that isn't possible, you may use write-through. As a last resort, you can also use uncached memory with the write-bugger enabled, but performance will suffer.
Implementing Your Own Driver (Driver Template)
The following sample driver offers a functional example to help you build your own display driver. Modify
PGUIDE_FB... macros as desired to match the requirements of your own device hardware.
Both of the following problems have a similar cause:
- Number keys: In the dialer application, when a number key is pressed to dial a phone number, the number doesn't display on the screen until after the next number has been pressed.
- Arrow keys: When an arrow key is pressed, the desired icon doesn't get highlighted. For example, if you browse through icons in the Applications menu, you might notice that icons aren't highlighted as expected when you use the arrow key to navigate between options.
Both problems are caused by an incorrect implementation of the frame buffer's page flipping. Key events are captured, but the graphical interface appears to drop every other frame.
Android relies on a double buffer to smoothly render page flips (please see Functionality for details).
This document explains the terminology, concepts, architecture, and basic mechanisms of the I/O Kit, Apple’s object-oriented framework for developing device drivers for OS X. It contains essential background information for anyone wanting to create device drivers for this platform.
Who Should Read This Document?
Download Pan Jit Input Devices Drivers
There are two general types of I/O Kit developers, and this document tries to be useful to both. The first type is the developer creating a device driver that is to be resident in the kernel; the second type is the application developer who is using an I/O Kit device interface to communicate with hardware. Some chapters contain information useful to both types of developers, and others contain information that is of interest only to writers of kernel-resident drivers.
Obviously there are things I/O Kit Fundamentals does not cover. It does not, for example, describe the use of the development tools or the use of specific driver programming interfaces. But it does help you to understand the hows and whys of the I/O Kit, enabling you to obtain the most value from the more specific documentation and examples.
Organization of This Document
Download Pan Jit Input Devices Driver Windows 7
I/O Kit Fundamentals gives a broad, conceptual description of the I/O Kit and device-driver development on OS X. It contains the following chapters:
Describes the features and benefits of the I/O Kit, and also discusses the philosophy and decisions informing its design.
Gives a high-level description of the I/O Kit’s architecture, essential concepts, and basic mechanisms.
Describes the I/O Registry, a dynamic database capturing the client/provider relationships among active driver objects.
Explains the matching process by which the most appropriate client drivers are found for registered providers. It also summarizes the procedure processes in user space follow to find suitable devices and their drivers.
Describes the base classes that each driver object directly or indirectly inherits from. It includes discussions of object construction and disposal, driver objects as I/O Registry entries, and the driver life cycle.
Explains the architecture and usage of work loops and event sources, mechanisms that the I/O Kit uses to process events such as interrupts and I/O requests in a protected single-threaded environment.
Describes how to use memory cursors, memory descriptors, and related objects to handle I/O transfers. It also discusses how drivers should deal with hardware constraints, such as those imposed by DMA engines.
Explains the concepts of OS X power management and describes different ways drivers can power-manage their devices.
Explains how to respond to device removal (hot-swapping).
Displays a class hierarchy chart for each family and provides family-specific information that might differ from generic I/O Kit information.
Provides a class hierarchy chart for all I/O Kit classes that are not members of a specific family.
Lists changes to this document.
Lists additional sources for information on OS X and related topics.
Defines key terms used in this document.
Once you’ve absorbed the information in I/O Kit Fundamentals, you should be able to forge ahead and actually create a device driver. Apple provides several documents and other sources of information to help you with your efforts:
IOKit Device Driver Design Guidelines describes the general steps required to design, code, debug, and build a device driver that will be resident in the kernel.
Accessing Hardware From Applications discusses how to use the I/O Kit’s “device interface” feature; it also includes information on serial and storage I/O via BSD device files.
Kernel Extension Programming Topics contains a collection of tutorials that introduce you to the development tools and take you through the steps required to create, debug, and package kernel extensions and I/O Kit drivers (a type of kernel extension). It also includes information on other aspects of kernel extensions.
Kernel Programming Guide provides an overview of the architecture and components of the OS X kernel environment (Mach, BSD, networking, file systems, I/O Kit). All developers who intend to program in the kernel (including device-driver writers) should read this document.
Mac Technology Overview provides an introduction to OS X as a whole, which is useful for developers new to the platform.
Of course, you can always browse the header files shipped with the I/O Kit, which are installed in
Kernel.framework/Headers/iokit (kernel-resident) and
IOKit.framework/Headers (device interface).)
You can also view developer documentation in Xcode. To do this, select Help from the Xcode menu and then click Show Documentation Window.
You can browse the BSD man pages for more information on BSD and POSIX APIs in two ways: You can type
manfunction_name in a Terminal window (for example,
man gdb) or you can view an HTML version at OS X Man Pages.
If you're ready to develop a universal binary version of a device driver to run in an Intel-based Macintosh, first read Universal Binary Programming Guidelines, Second Edition. Then, see IOKit Device Driver Design Guidelines for an overview of issues of particular interest to device driver developers. Related information that is specific to a particular device type is available in the documents listed at Hardware & Drivers Documentation.
Apple maintains several websites where developers can go for general and technical information on OS X.
Apple Developer Connection Reference Library (http://developer.apple.com/referencelibrary/index.html) contains a comprehensive collection of technical resources, including documentation, sample code, and Technical Notes.
Apple Developer Connection: OS X (http://developer.apple.com/devcenter/macosx) offers SDKs, release notes, product notes and news, and other resources and information related to OS X.
The AppleCare Support site (http://www.apple.com/support) provides a search feature that enables you to locate technical articles, manuals, specifications, and discussions on OS X and other areas.