TouchKey 2 click
PID: MIKROE-2474
TouchKey 2 click
has four capacitive pads powered by ATtiny817 which has an integrated
touch QTouch® controller. The click is designed to run on a 3.3V power supply. The four LEDs
onboard the click indicate when the Key (Pad) is pressed. TouchKey 2 click communicates with
the target microcontroller over UART interface (SPI interface is optional).
High moisture tolerance
You can use TouchKey 2 click in all kinds of conditions, without fearing something will happen
to it due to moisture and water droplets falling on it.
The plastic overlay on the TouchKey 2 click protects the board from moisture. Thanks to this
feature the electronic components are safe. The ATtiny817 has a driven shield for improved
moisture and noise handling performance.
ATtiny817 features
The Atmel® ATtiny817 is a microcontroller that uses an 8-bit AVR® processor with hardware
multiplier, running at up to 20MHz and with up to 8KB Flash, 512 bytes of SRAM and 128 bytes
of EEPROM.
ATtiny817 uses the latest technologies from Atmel® with a flexible and low power architecture
including Event System and SleepWalking, accurate analog features and advanced peripherals.
Capacitive touch interfaces with proximity sensing and driven shield are supported with the
integrated QTouch® peripheral touch controller.
The module supports wake-up on touch from power-save sleep mode.
Button features
Capacitive buttons can be toggled even when placed under a layer of glass or paper.
How it works
There are four LEDs for four touch keys. If key A is pressed LED_A is ON, etc. In addition,
there is UART communication between ATtiny817 and main MCU.
Note:
The header onboard the TouchKey 2 click can be used for device programming. Current
firmware sends data packets via UART (on which the demo example in our library is based).
SPI
communication
is possible with firmware modifications.
Key features
ATtiny817 module
o
Atmel® AVR® 8‐bit CPU
o
Running at up to 20MHz
o
128B EEPROM
o
256/512B SRAM
o
32.768kHz external crystal oscillator
UART interface (SPI optional)
3.3V power supply
Product Type
Applications
On-board modules
Key Features
Key Benefits
Interface
Power Supply
Compatibility
Click board size
Capacitive
A replacement for mechanical buttons
ATtiny817 from Microchip
Four capacitive touch pads, 3.3V power supply, protective plastic overlay
High moisture tolerance
UART (SPI is optional)
3.3V
mikroBUS
L (57.15 x 25.4 mm)
Pinout diagram
This table shows how the pinout on
TouchKey 2 click
corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
mikroBUS
tm
Pin
Notes
Not connected
Reset
SPI Chip Select
SPI Clock
NC
PC5_TARGET_RES
ET
PC3_SPI_SS
PC0_SPI_SCK
1
2
3
4
5
AN
RST
CS
SCK
MISO
PWM
INT
TX
RX
SCL
16
15
14
13
12
NC
NC
Not connected
Not connected
PA1_UART_TXD
UART transmit
PA2_UART_TXD
UART receive
NC
Not connected
SPI Master Input
PC1_SPI_MISO
Slave Output
SPI Master Output
PC2_SPI_MOSI
Slave Input
Power supply
Ground
+3.3V
GND
6
7
8
MOSI
3.3V
GND
SDA
5V
GND
11
10
9
NC
NC
GND
Not connected
Not connected
Ground
Buttons and LEDs
Designator
PWR
LD1
LD2
LD3
Name
PWR
A
B
C
Type (LED,
BUTTON…)
LED
LED
LED
LED
Description
Power Supply Indication LED.
Key A Press Indication LED
Key B Press Indication LED
Key C Press Indication LED
LD4
J1
D
PDI
LED
Header
Key D Press Indication LED
Programming header
Maximum ratings
Description
Power Supply Voltage
Current into VDD pin
Reset pin Voltage
I/O pin sink/source Current
Min
‐0.5
‐
‐0.5
‐40
Typ
3.3
100
3.3
‐
6
200
13
40
Max
V
mA
V
mA
Unit
Programming
Code examples for TouchKey 2 click, written for MikroElektronika hardware and compilers are
available on Libstock.
This code snippet initializes the MCU and display, and in an endless loop recognizes which key
is being pressed. The key that was touched last is shown on the display.
01
void
main(
void
)
02
{
03
system_init();
04
display_init();
05
06
TFT_Set_Font(
&HandelGothic_BT21x22_Regular,
CL_RED, FO_HORIZONTAL );
07
TFT_Write_Text(
"Press Any On-board Key",
50, 120
);
08
09
while(
true
)
10
{
11
// Key A has been pressed
12
if(
key_A_pressed
&&
old_key
!=
KEY_A )
13
{
14
display_key( "A", CL_RED );
15
key_A_pressed
=
false;
16
old_key
=
KEY_A;
17
}
18
// Key B has been pressed
19
else if(
key_B_pressed
&&
old_key
!=
KEY_B )
20
{
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
}
display_key( "B", CL_GREEN );
key_B_pressed
=
false;
old_key
=
KEY_B;
}
// Key C has been pressed
else if(
key_C_pressed
&&
old_key
!=
KEY_C )
{
display_key( "C", CL_BLUE );
key_C_pressed
=
false;
old_key
=
KEY_C;
}
// Key D has been pressed
else if(
key_D_pressed
&&
old_key
!=
KEY_D )
{
display_key( "D", CL_PURPLE );
key_D_pressed
=
false;
old_key
=
KEY_D;
}
}
https://shop.mikroe.com/click/hmi/touchkey-2 3/21/2017
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