|
Adafruit TSC2046 Touchscreen Arduino Library
|
This is a library for the TI TSC2046 resistive touchscreen.
Written by Qyriad qyriad@qyriad.me, 2023.
MIT license. All text above must be included in any redistribution.
Adafruit's TSC2046 breakout board will have 11 pins. At least 6 of those pins must be connected to use the touchscreen: Vin, GND, SCK, MISO, MOSI, and CS. Vin should be connected to +5V for 5V boards like the Arduino Uno, and +3V3 for 3.3V boards like the MKR Zero. You can find the voltage of your board in the "Tech Specs" section of the documentation for that board under "I/O Voltage".
The other 5 pins should be connected as follows:
| TSC2046 Breakout Pin | Arduino Pin |
|---|---|
| GND | GND |
| SCK | SCK |
| MISO | CIPO |
| MOSI | COPI |
| CS | SS |
Check the pinout for your board to see which pin numbers these correspond to. As an example, on the Arduino Uno, SCK, MISO, MOSI, and CS would be connected to D13, D12, D11, and D10 respectively.
The IRQ pin can be used to trigger an interrupt service routine whenever the touchscreen detects a touch. To do this, connect the IRQ pin to a digital pin on your Arduino board (see Adafruit's documentation on interrupts for what pins are usable for interrupts for each board), and "attach" the interrupt to an interrupt service routine. Again see Adafruit's documentation on attachInterrupt for more information, and see Adafruit_TSC2046::enableInterrupts for information on the TSC2046's interrupts specifically.
The Vbat pin can be used to measure some other voltage external to the touchscreen, though as the name suggests it is intended to measure a battery. To do this, connect the positive terminal of your battery to the Vbat pin, and the negative terminal to a common ground (GND), and call Adafruit_TSC2046::readBatteryVoltage to get its voltage. You can measure voltages (inclusively) between 0V and 6V this way.
The AUX pin, like the Vbat pin, can be used to measure some other voltage external to the touchscreen. Unlike Vbat, however, the maximum voltage this pin can measure is determined by the reference voltage, which by default is 2.5V. To measure higher voltages with this pin, take a look at the next paragraph which talks about VRef.
The VRef pin can be used to override the "reference voltage" that the TSC2046 uses to measure other voltages. The TSC2046 has an internal reference voltage of 2.5V that by default we use when measuring temperature, Vbat, and AUX voltages. Connecting a 5V supply to the VRef pin instead will allow us to use that as the reference voltage, which will increase the accuracy of voltage reads for temperature, Vbat, and AUX; and will also increase the range of voltage reads for AUX.
However, and this is important, if you connect something to the VRef pin, you must connect VRef to the same thing you connected Vin to.
If you do override the reference voltage, pass the voltage you're giving it as Adafruit_TSC2046::begin's vRef parameter.
Once you have your board connected up, interacting with it will be done with the Adafruit_TSC2046 class. First create an instance of this class (likely as a global variable), then call Adafruit_TSC2046::begin (usually in setup(). With that, you can call Adafruit_TSC2046::isTouched to check if the touchscreen is being touched, and then call Adafruit_TSC2046::getPoint to get the coordinates of the current touch. Adafruit_TSC2046::getPoint returns a TSPoint object, which contains the direct X and Y coordinates as point.x and point.y. You may also get the X and Y coordinates as percentages with point.xPercent() and point.yPercent(). The pressure is in point.z, and its value decreases as physical pressure increases.
xResistance — the value you pass here is something you must measure with a multimeter. Set your multimeter to measure resistance, place one probe on the pin-hole labeled "X-" on your TSC2046 breakout board, and place the other probe on the pin-hole labled "X+". Your multimeter should show you a number in ohms (Ω), the unit for resistance. Pass that number as the xResistance argument. If your multimeter gives you a value in kilohms (kΩ), divide that number by 1000 to get ohms and pass that value for the xResistance argument. If you do not have a multimeter or otherwise don't have a measurement, 400 (400Ω) is a reasonable value to use here, though note that the pressure measurements returned by Adafruit_TSC2046::getPoint may not be accurate in that case.Below is a simple example; a more complete example can be found in the examples/ directory.
1.8.13