參數(shù)資料
型號： HD66725
廠商： Hitachi,Ltd.
英文描述： Graphics LCD Controller/Driver with Key Scan Function(帶鍵掃描功能的圖形LCD控制器/驅(qū)動器)
中文描述： 圖形液晶顯示控制器/鍵掃描功能（帶鍵掃描功能的圖形液晶顯示控制器/驅(qū)動器驅(qū)動程序）
文件頁數(shù)： 59/117頁
文件大?。?/td> 834K
代理商： HD66725
HD66724/HD66725
59
Key Scan Control
The key matrix scanner senses and holds the key states at each rising edge of key strobe signals (KST) that
are output by the HD66724/HD66725. The key strobe signals are output as time-multiplexed signals from
KST0 to KST3. After passing through the key matrix, these strobe signals are used to sample the key state
of eight inputs KIN0 to KIN7, enabling up to 32 keys to be scanned.
The states of inputs KIN0 to KIN7 are sampled by key strobe signal KST0 and latched into the SCAN0
register. Similarly, the data sampled by strobe signals KST1 to KST3 is latched into the SCAN1 to SCAN3
registers, respectively. Key pressing is stored as 1 in these registers.
The generation cycle and pulse width of the key strobe signals depend on the operating frequency
(oscillation frequency) of the HD66724/HD66725 and the key scan cycle determined by the KF0 and KF1
bits. For example, when the operating frequency is 32 kHz and KF0 and KF1 are both 10, the generation
cycle is 4.0 ms and the pulse width is 1.0 ms. When the operating frequency (oscillation frequency) is
changed, the above generation cycle and the pulse width are changed in inverse proportion.
In order to compensate for the mechanical features of the keys, such as chattering and noise and for the
key-strobe generation cycle and the pulse width of the HD66724/HD66725, software should read the
scanned data two to three times in succession to obtain valid data. Multiple keypress combinations should
also be processed in the software.
Up to three keys can be pressed simultaneously. Note, however, that if the third key is pressed on the
intersection between the rows and columns of the first two keys pressed, incorrect data will be sampled. For
three-key input, the third key must be on a separate column or row.
The input pins KIN0 to KIN7 are pulled up to V
CC
with internal MOS transistors (see the Electrical
Characteristics section). External resistors may also be required to further pull the voltages up when the
internal pull-ups are insufficient for the desired noise margins or for a large key matrix.
SCAN0
SCAN1
SCAN2
SCAN3
D
03
D
02
D
01
D
00
D
13
D
12
D
11
D
10
D
23
D
22
D
21
D
20
D
33
D
32
D
31
D
30
KIN3 KIN2 KIN1 KIN0
(KST0
↑)
(KST1
↑)
(KST2
↑)
(KST3
↑)
D
04
D
14
D
24
D
34
KIN4
D
05
D
15
D
25
D
35
KIN5
D
06
D
16
D
26
D
36
KIN6
D
07
D
17
D
27
D
37
KIN7
KSD7 KSD6KSD5 KSD4KSD3 KSD2KSD1 KSD0
Figure 26 Key Scan Register Configuration
相關(guān)PDF資料
PDF描述
HD66726 Graphics LCD Controller/Driver with Key Scan Function(帶鍵掃描功能的圖形LCD控制器/驅(qū)動器)
HD66727 Low-Power Dot-Matrix Liquid Crystal Display Controller/Driver with Key Scan Function(帶鍵掃描功能的圖形LCD控制器/驅(qū)動器)
HD66728 112 x 80-dot Graphics LCD Controller/Driver(112 x 80點圖形LCD控制器)
HD66730 Dot-Matrix Liquid Crystal Display Controller/Driver(點陣液晶顯示控制器/驅(qū)動器)
HD66731 Dot-Matrix Liquid Crystal Display Controller/Driver(點陣液晶顯示控制器/驅(qū)動器)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HD66725A03TA0L 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD CONTROLLER
HD66726 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:128 x 128-dot Graphics LCD Controller/Driver with Four-grayscale Functions
HD66726A03TB0L 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Industrial Control IC
HD66727 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:Low-Power Dot-Matrix Liquid Crystal Display Controller/Driver with Key Scan Function
HD66727A03 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LCD Display Driver
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