POWER/RESET CLICK
PID: MIKROE-3771 Weight: 20 g
Power/Reset Click is equipped with two capacitive touch pads on a single click board™. It can be
activated by touch, and unlike the mechanical button, the capacitive touch button lasts much longer,
it is not prone to damage and wear over time and it is very reliable. Capacitive buttons are a very
popular method of powering up or resetting various devices. Besides the aforementioned benefits,
having a touch sensitive button on a device allows for a compact design, opens possibilities for
various kinds of human-machine interface and - it looks good and modern, especially if accompanied
by a LED that turns on when activated, just like the one on Power/Reset Click. This click board™
can find its place among many applications - for touch activated lighting controls, touch activated
control panels, toys and any other applications that need a switch or a button for powering and
resetting a device.
Power/Reset click board™ is supported by a mikroSDK compliant library, which includes functions
that simplify software development. This Click board™ comes as a fully tested product, ready to be
used on a system equipped with the mikroBUS™ socket.
Power/Reset click has two PCB pads, used to sense touch or proximity events. These
pads are the only elements on the top of the board, allowing installation of the protective
acrylic glass layer. These pads are marked as ON/OFF and RESET in order to offer to a
user a simple solution for a capacitive switching power and reset controls for various
devices. This click board™ includes all hardware and signal processing functions
necessary to provide stable sensing under a wide variety of changing conditions.
HOW DOES IT WORK?
Power/Reset Click is a capacitive touch sensing Click board™ which features
the QT1011, digital burst mode charge-transfer sensor that is capable of detecting near
proximity or touch, from Microchip. This click board™ has two PCB pads, used to sense
touch or proximity events. Besides the two touch sensitive pads, Power/Reset click has
two LED diodes for the touch indication. The two touch pads use two separate QT1011
ICs, providing a very reliable touch sensing functionality.
The AT42QT1011 is a digital burst mode charge-transfer sensor that is capable of
detecting nearproximity or touch, making it ideal for implementing touch controls. With
the proper electrode and circuit design, the self-contained digital IC will project a touch
or proximity field to several centimeters through any dielectric like glass, plastic, stone,
ceramic, and even most kinds of wood. It can also turn small metal-bearing objects into
intrinsic sensors, making them responsive to proximity or touch. This capability, coupled
with its ability to self-calibrate, can lead to entirely new product concepts.
The QT1011 is designed specifically for human interfaces like control panels,
appliances, toys, lighting controls, or anywhere a mechanical switch or button may be
found. It includes all hardware and signal processing functions necessary to provide
stable sensing under a wide variety of changing conditions. However, this click board™
is designed to serve as a power and reset capacitive switch panel board.
Besides the QT1011, this click board™ contains 74LVC1G74 as well. It is a Single Dtype flip-flop with set and reset. Because The output of the QT1011 is active-high upon
detection, the 74LVC1G74 is triggered by the positive edge of the ON/OFF touch pad. It
is wired in a cascade with the QT1011 in way that ensures holding one logical state until
the ON/OFF pad is pressed. Therefore, the ON/OFF pad acts like a switch, while the
RESET pad acts like a button, which is suitable for most common purposes.
The output signals for the ON/OFF and RESET pads are wired to the PWM and INT
pins on the mikroBUS™, respectively. Besides that, the STAT and RST LEDs are wired
parallel to the outputs in order to ensure a visible indication of the status of the pins.
This Click Board™ is designed to be operated only with 3.3V logic level. A proper logic
voltage level conversion should be performed before the Click board™ is used with
MCUs with logic levels of 5V.
SPECIFICATIONS
Type
Capacitive
Applications
Touch activated lighting controls, touch activated control panels,
toys and any other applications that need a switch or a button for
powering and resetting a device.
On-board
modules
QT1011, digital burst mode charge-transfer sensor that is capable
of detecting near proximity or touch, from Microchip.
Key Features
Reliable capacitive touch detection technology, noise filtering,
Patented spread-spectrum charge-transfer (direct mode),
Increased moisture tolerance
Interface
GPIO
Click board
size
M (42.9 x 25.4 mm)
Input Voltage
3.3V
PINOUT DIAGRAM
This table shows how the pinout on Power/Reset Click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
NC
1
AN
PWM
16
STA
ON/OFF Status Out
NC
2
RST
INT
15
RST
Reset Out
NC
3
CS
RX
14
NC
NC
4
SCK
TX
13
NC
NC
5
MISO
SCL
12
NC
NC
6
MOSI
SDA
11
NC
Power Supply
3.3V
7
3.3V
5V
10
NC
Ground
GND
8
GND
GND
9
GND
Ground
ONBOARD SETTINGS AND INDICATORS
Label
Name
Default
Description
LD1
STAT
-
ON/OFF Status Out
LD2
PWR
-
Power LED Indicator
LD3
RST
-
RESET Status
SOFTWARE SUPPORT
We provide a library for the Power/Reset click on our LibStock page, as well as a demo
application (example), developed using MikroElektronika compilers. The demo can run
on all the main MikroElektronika development boards.
Library Description
This library allows user to check which button is pressed or activated. Also initializes
GPIO driver. For more details check documentation.
Key functions:
void touchbutt_gpioDriverInit(T_TOUCHBUTT_P gpioObj) - This function initializes GPIO driver.
T_TOUCHBUTT_STATE touchbutt_getPWR( void ) - This function returns a state of the PWR pin
(ON/OFF button).
T_TOUCHBUTT_STATE touchbutt_getRST( void ) - This function returns a state of the RST pin
(RESET button).
Examples description
The application is composed of three sections :
System Initialization - Initializes peripherals and pins.
Application Initialization - Initializes GPIO driver and performs a timer interrupt configuration.
Application Task - (code snippet) - Checks the states of the PWR and RST pins and performs a
control of the timer counter depending on the pressed button (pins state). User can start and stop a
timer counter, in the resolution of 100ms, by pressing the ON/OFF button. Also can reset a timer
counter to 0 by pressing the RESET button. When timer counter was reached the target time (in
seconds), a message will be sent to the uart terminal and the sound will be generated. Timer counter
state will be showed to the uart terminal.
void applicationTask()
{
pwr_state = touchbutt_getPWR();
rst_state = touchbutt_getRST();
if ((pwr_state == _TOUCHBUTT_ACTIVE) && (time_cnt_prev != time_cnt) && (rst_state == _TOUC
HBUTT_INACTIVE))
{
time_val_dec = time_cnt / 10;
time_val_real = time_cnt % 10;
LongWordToStr( time_val_dec, text );
Ltrim( text );
mikrobus_logWrite( text, _LOG_TEXT );
mikrobus_logWrite( ".", _LOG_TEXT );
ByteToStr( time_val_real, text );
Ltrim( text );
mikrobus_logWrite( text, _LOG_LINE );
if ((time_val_dec >= target_time) && (alarm_flag == _TOUCHBUTT_ACTIVE))
{
mikrobus_logWrite( "** Target time is reached! **", _LOG_LINE );
alarm_flag = _TOUCHBUTT_INACTIVE;
Sound_Play( 1000, 50 );
Delay_ms( 40 );
Sound_Play( 1000, 50 );
Delay_ms( 40 );
}
}
if (rst_state == _TOUCHBUTT_ACTIVE)
{
time_cnt = 0;
alarm_flag = _TOUCHBUTT_ACTIVE;
}
else
{
time_cnt_prev = time_cnt;
}
}
The full application code, and ready to use projects can be found on our LibStock page.
Other mikroE Libraries used in the example:
Conversions
C_String
Sound
UART
Additional notes and informations
Depending on the development board you are using, you may need USB UART
click, USB UART 2 click or RS232 click to connect to your PC, for development systems
with no UART to USB interface available on the board. The terminal available in all
MikroElektronika compilers, or any other terminal application of your choice, can be
used to read the message.
MIKROSDK
This Click board™ is supported with mikroSDK - MikroElektronika Software
Development Kit. To ensure proper operation of mikroSDK compliant Click board™
demo applications, mikroSDK should be downloaded from the LibStock and installed for
the compiler you are using.
For more information about mikroSDK, visit the official page.
https://www.mikroe.com/power‐reset‐click/10‐9‐19