ucb1400 NXP Semiconductors, ucb1400 Datasheet - Page 25

• Manufacturer Part Number: ucb1400
• Description: Audio Codec With Touch Screen Controller And Power Management Monitor
• Manufacturer: NXP Semiconductors

Philips Semiconductors
10. Touch screen interface
9397 750 09611
Product data
Fig 17. Block diagram of the touch screen interface.
TM[1:0] = 00 OR 1X
10.1 Universal touch screen matrix
PXG, MXG, PYG, MYG
AD[3:0]
PXP, MXP, PYP, MYP
AV
SS
AI[2:0]
The UCB1400 contains a universal touch screen interface for 4-wire resistive touch
screen, capable of performing position, pressure and plate resistance
measurements. In addition, the touch screen can be programmed to generate
interrupts when the touch screen is pressed. The last mode is also active when the
UCB1400 is set in the stand-by mode.
The touch screen interface connects to the touch screen by four wires: TSPX, TSMX,
TSPY and TSMY. Each of these pins can be programmed to be floating, powered or
grounded in the touch screen switch matrix. The setting of each touch screen pin is
programmable by the PXP, MXP, PYP, MYP and PXG, MYG, PYG, MYG bits in the
touch screen control register. Possible conflicting settings (grounding and powering of
a touch screen pin at the same time) are detected by the UCB1400. In that case, the
UCB1400 will ground the touch screen pin.
Each of the four touch screen signals can be selected as input for the built-in 10-bit
ADC, which is used to determine the voltage on the selected touch screen pin in
position measurement mode. In addition, the UCB1400 can monitor touch screen
current via an internal 1 k resistor that can act as the input to the 10-bit ADC in
pressure or plate resistance measurement mode. The flexible switch matrix and the
multi-functional touch screen bias circuit enable the user of the UCB1400 to set each
desired touch screen configuration.
1 k
7:4
TSPX
0
Rev. 02 — 21 June 2002
ANALOG MUX
TSMX
1
0
TSPY
ANALOG MUX
2
TSMY
3
Audio codec with touch screen controller
1
TOUCH SCREEN
CURRENT MONITOR
and power management monitor
TM[1:0]=00
© Koninklijke Philips Electronics N.V. 2002. All rights reserved.
AV
TOUCH SCREEN
BIAS VOLTAGE
SS
TM[1:0] = 01
TO ADC INPUT
AV
DD
UCB1400
SN00246
BIAS
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