BU26154MUV_15 Datasheet, PDF (32/90 Pages) Rohm – Monaural Audio CODEC with Touch Panel Interface

BU26154MUV
Datasheet
Touch Screen Controller
SAR 12 bits ADC is integrated into this LSI and is available as 4 lines type touch screen controller.
There is the function of the X-axis, the position sensing of the Y-axis, the pen pressure detection and the pen interrupt
detection.
It becomes independent to Codec and is controllable without minding timing. But the hard reset (reset signal input by
RESETB pin) communizes it.
Clock control
When enabled clock is to be used for touch screen controller, set TCLKEN bit of Clock Enable Register to "1". The touch
screen controller function uses a built-in oscillator. Therefore it is not necessary to perform clock control listing in item
clock control when using only the touch screen controller.
Position sensing
This LSI is available for the position sensing of the touch screen. The twice measurement of the X-axis measurement, the
Y-axis measurement is necessary for position sensing.
BU26154
BU26154
XP
YP
refp
ainp
XP
YP
refp
ainp
ainn
YN
refn
XN
ainn
YN
refn
XN
At the time of the X-axis plate measurement
The Pen Pressure Detection
At the time of the Y-axis plate measurement
Figure 37
The measurement of touch pressure is carried out to measure the resistance between X plate and Y plate. It is calculable
by two methods, from the location information by location determination, and the measurement result in touch pressure
measurement mode.
In case of X-Position and Y-Position are known
Touch pressure resistance = X-plate resistance*(X-position/4096)*[(4096/Z1)-1] - Y-plate resistance*[1-(Y-position/4096)]
In case of X-Position is known
Touch pressure resistance = X-plate resistance*(X-position/4096)*[(Z2/Z1)-1]
BU26154
BU26154
XP
YP
refp
ainp
ainn
YN
refn
XN
At the time of Z1 point measurement
XP
YP
refp
ainp
ainn
YN
refn
XN
At the time of Z2 point measurement
Figure 38
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