Mobile Device Hardware Overview
4/19/2010
OEMs have a variety of hardware options when building Windows Mobile devices. The following illustration shows the different hardware components available for a typical Windows Mobile device.
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- Touch screen. The touch screen is an LCD covered by a resistive touch panel. Tapping the touch screen with a stylus or finger sends the same kind of messages that clicking with the left mouse button does on a desktop computer, although cursor support is limited to a spinning hourglass for wait signals. The user can also select and drag items. To sense quick changes in user input, the touch screen has a refresh rate of at least 100 samples per second.
- Stylus and keyboard. Windows Mobile devices do not have a standard, physical keyboard. Text input is accomplished by using the input panel and the stylus. Generally, the input panel is a standard window on the touch screen that displays an input method, enabling users to enter data in a variety of ways. Windows Mobile Professional and Windows Mobile Classic includes a simplified QWERTY keyboard input method and a handwriting recognition input method. The stylus is a pointer for accessing a touch screen and input methods.
- Hardware keys. Windows Mobile devices come with several hardware keys, which can be pressed, held down, double-clicked, or pressed in combination with other keys. These keys allow a user to start applications, navigate lists, open records, and close fields and dialog boxes, and the behavior of some of these keys can be programmatically modified.
For more detailed information about hardware keys and how to perform associated programming tasks, see the Navigation Keys and Program Keys topics in this section. - Audio input. For devices that support audio, a built-in microphone is usually located on the front of the device so that a user can view the screen while recording. The codec software is identical to a desktop computer's audio compression manager (ACM). OEMs may add a microphone jack for an external microphone. The jack is transparent to the software.
- Audio output. You can use the built-in speakers to play sounds associated with notification events. You can also use the speakers to play voice recordings, other .wav files, or for dual tone multi-frequency (DTMF) dialing output. Some OEMs may add a headphone jack for headphones, external speakers, or other audio-out hardware. This jack is transparent to the software.
- Notification options. An OEM may provide several notification options for a device: audio, a flashing light-emitting diode (LED), or vibration controls such as those on cellular phones and pagers.
- Power. A Windows Mobile device can run many hours on its standard battery source, and it also has a backup battery to avoid data loss if the primary battery loses power.
- CPU. Windows Mobile devices use the ARM family of CPUs. The ARM processors offer an excellent combination of high performance and low power consumption.
- Memory. Windows Mobile devices come with a minimum amount of of RAM depending on the SKU.
Because it is important to conserve memory on Windows Mobile devices, many of the device operating system components are compressed in ROM. When a user needs a component, the operating system decompresses that component and transfers it to RAM. - Built-in serial port. Windows Mobile devices come with a built-in serial port, and some OEMs may include a second serial port. A Windows Mobile device can connect to a desktop computer by using a serial cable or an optional docking cradle, available from many device manufacturers, that is connected to the desktop computer. Some devices support data communications through a modem connected to the cradle.
- Infrared communications serial port. Windows Mobile devices include a serial port that conforms to Infrared Data Association (IrDA) specifications. Windows Mobile devices can communicate with other Windows Mobile devices, other Windows Embedded CE–based devices, handheld computing devices, or desktop computers.
- Storage card slots. Many Windows Mobile devices include one or more storage card slots that you can use for removable memory cards of various types. These cards are commonly used for media (such as music or pictures), applications, or data storage. Some devices also have a section of internal persistent memory that behaves like a storage card, although it is not removable. See File and Application Management for information about programming options related to storage cards.