sx8652 Semtech Corporation, sx8652 Datasheet - Page 24

• Manufacturer Part Number: sx8652
• Description: 15kv Esd Low Power 4-wire / 5-wire Resistive Touchscreen Controller With Spi Interface
• Manufacturer: Semtech Corporation

6.4. Power-Up
Figure 21.
6.5. Reset
The POR of the SX8652 will reset all registers and states of the SX8652 at power-up.
Additionally the host can reset the SX8652 by asserting the NRST pin (active low) and also via the SPI bus.
If NRST is driven LOW, then NIRQ will be driven low by the SX8652. When NRST is released (or set to high) then NIRQ
will be released by the SX8652.
The circuit has also a soft reset capability. When writing the code 0xDE to the register RegSoftReset, the circuit will be
reset.
7. Modes of Operation
The SX8652 has four operation modes that are configured using the SPI commands as defined in Table 10 and Table 13.
These 4 modes are:
At startup the SX8652 is set in manual mode.
In the manual mode the SX8652 is entirely stopped except for the SPI peripheral which accepts host commands. This
mode requires RATE equal to be zero (RATE = 0, see Table 13).
In the automatic mode the SX8652 will sequence automatic channel conversions. This mode requires RATE to be larger
than zero (RATE > 0, see Table 13).
In the PENDET mode the pen detection is activated. The SX8652 will generate an interrupt (NIRQ) upon pen detection and
set the PENIRQ bit in the SPI status register. To quit the PENDET mode the host needs to configure the manual mode.
In the PENTRG mode the pen detection is activated and a channel conversion will start after the detection of a pen. The
SX8652 will generate an interrupt (NIRQ) upon pen detection and set the CONVIRQ bit in the SPI status register. To quit
the PENTRIG mode the host needs to configure the manual mode. The PENTRG mode offers the best compromise
between power consumption and coordinate throughput.
Revision V1.6/July 2010
©2010 Semtech Corp.
ADVANCED COMMUNICATIONS & SENSING
manual (command ‘MANAUTO’ and RATE=0),
automatic (command ‘MANAUTO’ and RATE>0),
pen detect (command ‘PENDET’),
pen trigger mode (command ‘PENTRG’).
voltage
voltage
NIRQ
VDD/2
VDD
Power-up, NIRQ
t
POR
time
time
15kV ESD Low Power 4-Wire / 5-Wire Resistive
Page 24
The NIRQ pin is kept low during SX8652 power-up.
During power-up, the SX8652 is not accessible and SPI
communications are ignored.
As soon as NIRQ rises, the SX8652 is ready for SPI
communication.
Touchscreen Controller with SPI Interface
www.semtech.com
DATASHEET
SX8652