SX8650 Datasheet, PDF (19/56 Pages) Semtech Corporation – World’s Lowest Power & Smallest Footprint 4-wire Resistive Touchscreen Controller with 15kV ESD

SX8650
World’s Lowest Power & Smallest Footprint 4-wire
Resistive Touchscreen Controller with 15kV ESD
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
3.3. Host Interface and Control Pins
The SX8650 host and control interface consists of: NIRQ, I2C pins SCL and SDA, A0, and NRST.
3.3.1. NIRQ
The NIRQ pin is an active low, open drain output to facilitate interfacing to different supply voltages and thus requires an
external pull-up resistor (1-10 kOhm). The NIRQ pin does not have protection to VDD.
The NIRQ function is designed to provide an interrupt to the host processor. Interrupts may occur when a pen is detected,
or when channel data is available.
Figure 11 shows a simplified diagram of the NIRQ pin.
HOST
VDD
NIRQ
IRQ
Control
Figure 11. Simplified diagram of NIRQ
3.3.2. SCL
The SCL pin is a high-impedance input and open-drain output pin. The SCL pin does not have protection to VDD to
conform to I2C slave specifications. An external pull-up resistor (1-10 kOhm) is required.
Figure 12 shows the simplified diagram of the SCL pin.
HOST
VDD
SCL
SCL
IN
I2C
OUT
Figure 12. Simplified diagram of SCL
3.3.3. SDA
SDA is an I/O pin. It can be used as an open-drain output (with external pull-up resistor) or as an input. An external pull-up
resistor (1-10 kOhm) is required.
The SDA I/O pin does not have protection to VDD to conform to I2C slave specifications.
Figure 13 shows a simplified diagram of the SDA pin.
ACS Revision V2.15/October 2009
©2009 Semtech Corp.
Page 18
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