45 lines
1.4 KiB
Markdown
45 lines
1.4 KiB
Markdown
|
# 1-Wire Thermometer
|
||
|
|
This example application demonstrates the use of the 1-Wire library with a DS18B20 thermometer.
|
||
|
|
It also covers basic GUI, input handling, threads and localisation.
|
||
|
|
|
||
|
|
## Electrical connections
|
||
|
|
Before launching the application, connect the sensor to Flipper's external GPIO according to the table below:
|
||
|
|
| DS18B20 | Flipper |
|
||
|
|
| :-----: | :-----: |
|
||
|
|
| VDD | 9 |
|
||
|
|
| GND | 18 |
|
||
|
|
| DQ | 17 |
|
||
|
|
|
||
|
|
*NOTE 1*: GND is also available on pins 8 and 11.
|
||
|
|
|
||
|
|
*NOTE 2*: For any other pin than 17, connect an external 4.7k pull-up resistor to pin 9.
|
||
|
|
|
||
|
|
## Launching the application
|
||
|
|
In order to launch this demo, follow the steps below:
|
||
|
|
1. Make sure your Flipper has an SD card installed.
|
||
|
|
2. Connect your Flipper to the computer via a USB cable.
|
||
|
|
3. Run `./fbt launch_app APPSRC=example_thermo` in your terminal emulator of choice.
|
||
|
|
|
||
|
|
## Changing the data pin
|
||
|
|
It is possible to use other GPIO pin as a 1-Wire data pin. In order to change it, set the `THERMO_GPIO_PIN` macro to any of the options listed below:
|
||
|
|
|
||
|
|
```c
|
||
|
|
/* Possible GPIO pin choices:
|
||
|
|
- gpio_ext_pc0
|
||
|
|
- gpio_ext_pc1
|
||
|
|
- gpio_ext_pc3
|
||
|
|
- gpio_ext_pb2
|
||
|
|
- gpio_ext_pb3
|
||
|
|
- gpio_ext_pa4
|
||
|
|
- gpio_ext_pa6
|
||
|
|
- gpio_ext_pa7
|
||
|
|
- ibutton_gpio
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define THERMO_GPIO_PIN (ibutton_gpio)
|
||
|
|
```
|
||
|
|
Do not forget about the external pull-up resistor as these pins do not have one built-in.
|
||
|
|
|
||
|
|
With the changes been made, recompile and launch the application again.
|
||
|
|
The on-screen text should reflect it by asking to connect the thermometer to another pin.
|