CRTOUCH Datasheet, PDF (6/68 Pages) Freescale Semiconductor, Inc – Capacitive and Resistive Touch Sensing Application Specific IC.

Pins and Connections
1.4 Signals description
Table 1. Signal descriptions
Pin
1
2
3
4
5
6
7
8
9-11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Function used
for CRTouch
Description
Yr
TouchPending
5WUR
Y+ / 5WLR
X+ / 5WS
Y– / 5WUL
VDDA
VSSA
NC
VREG_IN
V33_OUT
VSS
X– / 5WLL
Electrode1
Xr
Electrode2
Electrode3
Electrode4
NC
Baudrate Auto
Detect
I2CAddrSel
VDD
VSS
I2C1_SDA
I2C1_SCL
Reset
Com Select
Wakeup
UART_RX
UART_TX
Y voltage reference
Indicates that there is a previous touch event (resistive or capacitive)
fwhere data registers have not been read
5-Wire Upper Right Connection
4-Wire Y+ or 5-Wire Lower Right connection
4-Wire X+ or 5-Wire Sense connection
4-Wire Y– or 5-Wire Upper Left connection
V_DD Signal for the ADC
V_SS Signal for the ADC
No Connect
Voltage regulator Input
Voltage regulator output –3.3 Volts
V_SS – Connect to Digital Ground
4-Wire X– or 5-Wire Lower Left connection
Capacitive Touch Sensing Key #1
X voltage reference
Capacitive Touch Sensing Key #2
Capacitive Touch Sensing Key #3
Capacitive Touch Sensing Key #4
No Connect
Signal used to enable Baud Rate auto detection
I2C Address Selection pin is used as bit 1 of the I2C address
V_DD – Connect to system regulated power supply
V_SS – Connect to digital Ground
I2C – Bidirectional SDA communication signal
I2C – Clock signal. Must be driven by the bus master
Reset signal
Communication Select Pin. 0 = UART. 1 = I2C
Signal used to wake the CRTouch when configured to go into Sleep
or Shutdown modes. While in Sleep mode, this pin should be held
down with a logical 0 to communicate with the device.
UART Reception pin
UART Transmission pin
CRTouch Data Sheet, Rev. 3
6
Freescale Semiconductor