To go on you must click anywhere on the screen. After you did this a menu will turn up, where you can choose the way you want to type in your values for the on/off values and the time of checking.
You can decide between two variations. You can type in the values via a “Num Pad Input Mode” or via a “Slider Input Mode”.
“Slider Input Mode”.
Min/Max value: 0-99°C in steps of 2°C
Refresh Time: 0-50ms in steps of 1ms
“Num Pad Input Mode”
Min/Max value: 0-99°C in steps of 1°C
Refresh Time: 0-1000ms in steps of 1ms
If you decide to type in the values via the “Num Pad Input Mode” the numeric keypad arise. There you can type in step by step your values for the minimum and maximum temperature and the checking time. If you click on “Ok” the transmission begins. If you click on the arrow you can correct your previous entry. An error comes up if the minimum temperature is higher than the maximum value or if the checking time is higher than 50ms.
Use the “Ok” button to go on to the next value to enter or the “<-“button to return to the previous value. Mistyping can be corrected. If all digits are field, the cursor returns to the first position to reenter the value.
If you decide to use the “Slider Input Mode” you can also choose the values for the on/off state and the checking time. You must slide over the LCD-display to change these values. The values are shown above the timber. If you click on “Ok” the transmission begins.
After your settings the transmission starts. If the controller heats up a flame is shown on the display. It means that the capacitor loads up (actual temperature is increasing) until it reached your maximum voltage (maximal temperature).
If the controller cools down a snowflake is shown on the display. It means that the capacitor discharge (actual temperature is decreasing) until it reached your minimum voltage (minimal temperature).
Picture Converter
To draw a picture on the screen or to customize the cover screen you can use our Picture to Pixel converter tool.
First you need a picture with maximum size of 160x80 pixels and of the picture file format bmp. The pixels, which should be drawn on the screen, have to be colored black.
Start the program and open the picture with the “Open” button.
Choose a function name (c naming rules) and an offset/variable name (c naming rules) for the picture position on the screen.
You can use the variable as defines (for example #define pos_x 13) or as parameters to call the function.
Click on “Generate” to create your function. You can copy the code into your main.c or use the “Save” button to save the function into an individual c file and call it from your main.c.
Simulation & Measurements
R-C Network 1st Order
• R1 = 10000?
• C1 = 1000µF
• S1 Reset button for rapid discharge of C1
• Measurement point A for µC analog input
• +5V digital output of µC
• GND of µC
The R-C network is simulating a thermal system. We can simulate for example room temperature control or a water heater for a bathroom. R1 limits the current which is used to charge C1. The time constant tau represents the time needed to reach 63.2% of the supplied voltage across C1.
The charging and discharging process is observed by a microcontroller (analog measurement of the voltage across C1). If the measured value (actual temperature) is smaller or equal to the minimum voltage level (minimum temperature) the microcontroller supplies the system with 5V and the capacitor starts charging (temperature is increasing). If the measured value (actual temperature) is bigger or equal to the maximal voltage level (maximal temperature) the microcontroller is setting the supply pin to 0V and the capacitor starts discharging (temperature is decreasing).
LABView Measurements
The charging and discharging of C1 was captured with LABView.
Setup for room temperature control:
• R1 = 10000?, C1 = 1000µF
• Minimal temperature: 18°C
• Maximal temperature: 21°C
• Refresh time: ~0ms
Rising time Tr: 3.00s - 1.25s = 1.75s
On time Ton: 5.06s - 4.68s = 0.38s
Off time Toff: 6.50s - 5.06s = 1.44s
Duty Cycle: g = Ton / Ton + Toff = 0.38s / 0.38s + 1.44s = 0.21 = 21%
Distortion of the system
The same values and system were used to generate with LABView the distortion behavior of the system.
After the system was disturbed, the microcontroller adjusts the system back to the given parameters.
Ports & Pins
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Port F (a/d converter, touch control)
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Pin 7
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Pin 6
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Pin 5
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Pin 4
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Pin 3
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Pin 2
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Pin 1
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Pin 0
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x
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x
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x
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x
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x
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A/D (x) +
Digital
Output (y)
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A/D (y) +
Digital output (x)
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A/D
(analogue input)
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Port C (LCD data bus)
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Pin 7
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Pin 6
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Pin 5
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Pin 4
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Pin 3
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Pin 2
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Pin 1
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Pin 0
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D7
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D6
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D5
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D4
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D3
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D2
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D1
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D0
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Port A (LCD control bus, touch control)
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Pin 7
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Pin 6
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Pin 5
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Pin 4
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Pin 3
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Pin 2
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Pin 1
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Pin 0
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RS
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Enable
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R/W
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x
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x
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x
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x
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Touch
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Port D (system supply)
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Pin 7
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Pin 6
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Pin 5
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Pin 4
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Pin 3
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Pin 2
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Pin 1
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Pin 0
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x
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x
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x
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x
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x
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x
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x
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5V/0V
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GND à connected to GND of microcontroller
5V à connected to 5V output of microcontroller
Define Settings
Show flame and flake for heating/cooling status
#define FLAME_AND_FLAKE_ON
Show grad sign in front of Celsius
#define GRAD_ON
Show cover screen
#define COVER_ON
Show current temperature, refresh automatically
#define SHOW_AD_VALUE
Live update of the graph
#define LIVE_DIAGRAM_ON Customize to Other Microcontroller Boards
Using the define statements on top of the main.c it’s easily possible to customize the used ports to other microcontroller boards using the same chip (like the EVA board).
Change the define statements to your specific controller setup.
Hardware Setup
The display data port is initially set to port C. Change it for example to port B: DDRB, PORTB, PINB.
// Display Data Port
#define LCD_DATA_DDR DDRC
#define LCD_DATA_PORT PORTC
#define LCD_DATA_PIN PINC The display control port is initially set to port A. Change it for example to port B: DDRB, PORTB.
// Display Control Port
#define LCD_CTRL_DDR DDRA
#define LCD_CTRL_PORT PORTA Change the display control pins to your setup.
// Display Control Pins
#define LCD_CTRL_RS 7
#define LCD_CTRL_RW 5
#define LCD_CTRL_E 6 Change the digital output pin for the touch panel to your setup. For example ‘b’ (lower case letter with ’’)
Change the analogue port to your chosen setup.
// Touch Control
#define TOUCH_DIGIT_OUT_PORT 'a'
#define TOUCH_DIGIT_OUT_PIN 0
#define TOUCH_ANA_PORT 'f' The r-c network is supplied with port d, pin 0. Change it to your setup.
// System Control
#define SYS_SUPPLY_PORT 'd'
#define SYS_SUPPLY_PIN 0
Flowchart
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