144 lines
3.6 KiB
C
Executable File
144 lines
3.6 KiB
C
Executable File
#include "main.h"
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const char* lm35_string = "LM35 Temp: ";
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const struct {
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x = sizeof(lm35_string);
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y = 0;
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} lm35_value_pos;
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#ifdef CALIBRATION
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const char* diode_string = "Diode Value: ";
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#else
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const char* diode_string = "Diode Temp: ";
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#endif
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const struct {
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x = sizeof(diode_string);
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y = 1;
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} diode_value_pos;
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/** @brief Initialises general pins for use.
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*
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* @note Does not initialise LCD pins. That is handled by lcdlibrary
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*/
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void pin_init() {
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/* Pin Mappings:
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* PC0 -> ADC0 input for diode measurement
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* PC1 -> ADC1 input for LM35
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*/
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// Pin Config for Diode ADC
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DDRC &= ~(1 << DDRC0);
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DIDR0 |= (1 << ADC0D); // Disable digital input
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// Pin Config for LM35 ADC
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DDRC &= ~(1 << DDRC1);
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DIDR0 |= (1 << ADC1D); // Disable digital input
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}
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/** @brief Initializes ADC with required settings
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*/
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void adc_init() {
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/* ADC Settings
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* Use Aref as Vref
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* Initially set input as GND
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* Data right-adjusted
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* No Interrupts
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*/
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// Set MUX[3:0] to 0b1111 (GND reference)
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ADMUX |= (1 << MUX3) | (1 << MUX2) | (1 << MUX1) | (1 << MUX0);
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// Make sure data is right adjusted
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ADMUX &= ~(1 << ADLAR);
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// Set the clock prescaler to 128 (slower ADC means more accurate measurements)
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ADCSRA |= (1 << ADPS2) | (1 << ADPS1) (1 << ADPS0);
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// Enable ADC
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ADCSRA |= (1 << ADEN);
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}
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/** @brief Blocking function to read an ADC conversion from a selected ADC input.
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*
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* @note Blocks until conversion finishes, so speed of this function is dependant
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* on ADC prescaler.
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*/
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uint16_t adc_run_conversion(uint8_t adc_selection) {
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// Select ADC
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ADMUX &= 0xF0 | adc_selection;
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// Start conversion
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ADCSRA |= (1 << ADSC);
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// Wait until conversion is complete
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while (ADCSRA & (1 << ADIF));
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// Read out conversion value
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// may not be correct
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return ADC;
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}
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/** @brief Converts an ADC value from a measurement on an LM35 into a temperature.
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*/
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float lm35_convert(uint16_t adc_reading) {
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return (float) (adc_reading * ADC_VREF / ADC_RESOLUTION) / LM35_SENSITIVITY;
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}
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/** @brief Converts and ADC value from a measurement on a diode into a temperature.
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* TODO
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*/
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float diode_convert(uint16_t adc_reading) {
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// Do some funky math here
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return 0;
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}
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int main() {
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// Initialise peripherals
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pin_init();
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adc_init();
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// Initialise display
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// NOTE: LCD uses PB0-PB6
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lcd_init(LCD_DISP_ON);
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// Write "base" strings to LCD
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lcd_puts(lm35_string);
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lcd_gotoxy(0, diode_value_pos.y); // Switch to bottom
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lcd_puts(diode_string);
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// Note that special compiler/linker flags have to be added to enable
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// printf-ing floats
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// See: https://startingelectronics.org/articles/atmel-AVR-8-bit/print-float-atmel-studio-7/
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while (1) {
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// Read LM35 value, and write to LCD
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float lm35_temp = lm35_convert(adc_run_conversion(1));
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// Convert measured value to string
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char[6] lm35_temp_str;
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sprintf(lm35_temp_str, "%3.1f", lm35_temp);
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// Display temp on LCD
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lcd_gotoxy(lm35_value_pos.x, lm35_value_pos.y);
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lcd_puts((const char*) lm35_temp_str);
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// Read diode value, and write to LCD
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#ifdef CALIBRATION
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uint16_t diode_value = adc_run_conversion(0);
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char[6] diode_str;
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sprintf(diode_str, "%d", diode_value);
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#else
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float diode_temp = diode_convert(adc_run_conversion(0));
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char[6] diode_str;
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sprintf(diode_str, "%3.1f", diode_temp);
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#endif
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// Display diode info on LCD
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lcd_gotoxy(diode_value_pos.x, diode_value_pos.y);
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lcd_puts((const char*) diode_str);
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}
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}
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