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參數(shù)資料
| 型號(hào)： | UR5HCFJ8-P |
| 廠商： | Semtech Corporation |
| 英文描述： | Low-Power Keyboard Encoder for Portable Systems |
| 中文描述： | 低功耗便攜式鍵盤(pán)編碼器系統(tǒng) |
| 文件頁(yè)數(shù)： | 4/16頁(yè) |
| 文件大?。?/td> | 195K |
| 代理商： | UR5HCFJ8-P |
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KEYBOARD ENCODER, (CON
’
T)
MODE CONTROL
Copyright Semtech, 1997-2001
DOC5-FJ 8-DS-107
www.semtech.com
4
Embedded Numeric K eypad
The UR5HCFJ 8 implements an
embedded numeric keypad. The
Numeric Keypad Function is
invoked by pressing the Num Lock
Key.
FN K ey
A special FN Key has been
implemented to perform the
following functions while it is held
pressed:
Function Key F1 becomes F11
Function Key F2 becomes F12
Ctrl Left Key becomes Ctrl Right
Alt Left Key becomes Alt Right
If Num Lock is set:
Embedded numeric keypad keys
become regular keys.
If Num Lock is not set:
Embedded numeric keypad keys
provide the same codes as a
numeric keypad when the Num
Lock is not set (Arrow Keys, PgUp,
PgDn, etc.)
S tatus LED indic ators
The controller provides interfacing
for three LED shift status indicators.
All three pins are active low to
indicate the status of the host
system (Num Lock, Caps Lock and
Scroll Lock). They are set by the
system (AT/PS/2 protocol).
Operating modes are defined by the logic level of the mode pin in the Mode
Control Unit.
N-K ey Rollover
In this mode, the code(s) corresponding to each key press are transmitted
to the host system as soon as that key is debounced, independently of the
release of other keys. If a key is defined to be Typematic, the
corresponding code(s) will be transmitted while that key is held pressed.
When the key is released, the corresponding break code(s) are then
transmitted to the host system. If the released key happens to be the most
recently pressed, then Typematic Action is terminated. There is no limitation
to the number of keys that can be held pressed at the same time. However,
two or more key closures, occurring within a time interval of less than 5 mS,
will set an error flag and will not be processed. This procedure protects
against the effects of accidental key presses.
“Ghost” K eys
In any scanned contact switch matrix, whenever three keys defining a
rectangle on the switch matrix are held pressed at the same time, a fourth
key positioned on the fourth corner of the rectangle is sensed as being
pressed. This is known as the
“
ghost
”
or
“
phantom
”
key problem. Although
the problem cannot be totally
eliminated without using external
hardware, there are methods to
neutralize its negative effects for most
practical applications. Keys that are
intended to be used in combinations or
are likely to be pressed at the same
time by a fast typist (i.e., keys located
in adjacent positions on the keyboard)
should be placed in the same row or
column of the matrix, whenever
possible. Shift keys (Shift, Alt, Ctrl)
should not reside in the same row (or
column) with any other keys.
The UR5HCFJ 8 has built-in mechanisms to detect the presence of
“
ghost
”
keys, thus eliminating the necessity of external hardware.
Actual key presses
“
Ghost
”
Key
Figure 1:
“
Ghost
”
or
“
Phantom
”
Key
Problem
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| UR5HCFJL | THERMISTOR NTC 3K OHM @ 25C |
| UR5HCFJL-FB | Zero-PowerTM Keyboard Encoder for Portable Systems |
| UR5HCFJL-FN | Zero-PowerTM Keyboard Encoder for Portable Systems |
| UR5HCFJL-P | Zero-PowerTM Keyboard Encoder for Portable Systems |
| UR5HCSPI-06 | Zero-PowerTM Keyboard Encoder & Power Management IC for H/PCs |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| UR5HCFJL | 制造商:SEMTECH 制造商全稱(chēng):Semtech Corporation 功能描述:Zero-PowerTM Keyboard Encoder for Portable Systems |
| UR5HCFJL-06-P | 制造商:未知廠家 制造商全稱(chēng):未知廠家 功能描述:ENCODER|DIP|40PIN|PLASTIC |
| UR5HCFJL-16-P | 制造商:未知廠家 制造商全稱(chēng):未知廠家 功能描述:ENCODER|DIP|40PIN|PLASTIC |
| UR5HCFJL-FB | 制造商:SEMTECH 制造商全稱(chēng):Semtech Corporation 功能描述:Zero-PowerTM Keyboard Encoder for Portable Systems |
| UR5HCFJL-FN | 制造商:SEMTECH 制造商全稱(chēng):Semtech Corporation 功能描述:Zero-PowerTM Keyboard Encoder for Portable Systems |
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