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NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
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Revision V1.30
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Key Pad Scan
5.32.5.8
Take A_2 as input, and select AVDD33 and AGND33 as the reference. For ADC configure
register KPC_EN (ADC_CONF[9]) should be set to 1.
Key Pad
Key Pad
AVDD33
AVDD33
ADC
Res1
Res1
A_2
A_2
Res2
Res2
On board
On board
Figure 5.32-5 Key Pad Detection Diagram
If a user applies the Keypad using this structure and meanwhile, he/she needs the interrupt
generator, please make sure Res1≤20K ohm and Res2<5.6*Res1. Moreover, a 0.01uF cap is
recommended at A_2 on board.
If a user doesn’t need the interrupt generator, please ignore the requirement for Res1 and Res2.
4-wire and 5-wire Touch Screen
5.32.5.9
The touch screen control logic and the switch could control the 4-wire and 5-wire type touch
screen. For ADC configure register T_EN (ADC_CONF[0]) should be set to 1.ADC control register
WMSWCH (ADC_CTL[16]) (Wire Mode Switch) for 5-wire/4-wire configuration. The following
figures show the interface for 4-wire, 5-wire touch screen respectively.
Note that, the four switches to bias XP, XM, YP, YM have conduction resistance under 5 ohm.
And the pull up PMOS have 200K ohm typically.