QST104 STMicroelectronics, QST104 Datasheet - Page 12

• Manufacturer Part Number: QST104
• Description: Capacitive touch sensor device 4 keys
• Manufacturer: STMicroelectronics

Device operating modes
Caution:
4.4
4.5
4.5.1
12/45
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If an I
does not acknowledge the frame (even if it has an I
host must therefore send again the frame until it is taken in account and acknowledged.
Mode selection
The device options are configured by connecting pull-up or pull-down resistors on OPTn
pins. The device operating mode is selected using option pin 1 (OPT1) while the device
settings are configured using option pins OPT2 to OPT6
at power-up and after a reset.
To fit most applications, the QST104 device offers two different operating modes:
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Table 3.
Stand-alone mode
This mode allows the user to simply replace existing mechanical switch interface with a
capacitive sensing solution. It is designed for maximum flexibility and can accommodate
most popular sensing requirements via option resistors (see
Main features
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Pin OPT1 is high at start-up Stand-alone mode
Pin OPT1 is low at start-up
Deep Sleep mode
In Deep Sleep mode, the device enters a very low power mode indefinitely. The device
resumes its operations after receiving an I
Stand-alone mode
This mode allows the user to simply replace existing mechanical switches with a
capacitive sensing solution. It is designed for maximum flexibility and can
accommodate most popular sensing requirements via option resistors (AKS, Low
power, Max On-Duration and output modes).
In this mode, the 4 output pins reflect the status of the 4 sensing channels.
I
In this mode, which is the most open one, the device is driven using the I
To avoid polling, the QST device features an output interrupt pin (IRQ). The IRQ line
reports all key changes to the Master device. The QST (Slave) device can drive up to
13 general-purpose outputs.
Pins KOUT1 to KOUT4 directly reflect the state of keys
Selectable global adjacent key suppression (AKS™)
Selectable sleep duration
Selectable Max On-Duration values
Selectable BCD mode
2
2
C mode
C frame is received while in Sleep or Deep Sleep mode, the device wakes up but
Operating modes
OPT1: Mode selection
I
2
C mode
2
C frame with any address or a reset.
ADD0
OPT2
AKS
2
C frame with the device address). The
(Table
Option resistor function
ADD1
OPT3
LP
Figure
3). Option pins are sampled
MOD_0 MOD_1
OPT4
ADD2
3).
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Unused Unused
OPT5
2
C interface.
QST104
OPT6
OM