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main.c

+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include "pico/stdlib.h"
+#include "hardware/gpio.h"
+#include "hardware/adc.h"
+#include "lib/fonts.h"
+#include "lib/st7735.h"
+
+//this task covers how to use the on-board temperature sensor in the RP2040 chip on the Raspberry pi Pico
+//it uses the analogue to digital converter (ADC) in the Pico to read the internal temperature of the RP2040 and
+//does the necessary data conversion to output the temperature of the chip
+
+//also covers how to perform the required data processing to take the raw ADC output and convert it
+//into a voltage and then into temperature
+
+//the temperature sensor might not be calibrated so temperatures might differ in different
+//boards due to manufacturing inconsistencies
+//as such, if you will be using this in a serious project that requires an accurate temperature value,
+//I would recommend using an external sensor.
+
+int main() {
+
+    stdio_init_all();  // Initialise serial in/output
+
+    //Configure ADC
+    adc_init();
+    adc_set_temp_sensor_enabled(true);  //Enable temperature sensor
+    adc_select_input(4);  //Select fifth channel of the adc as the input
+
+    sleep_ms(1000);  // Wait 1 sec
+    ST7735_Init();  // Initialise the screen
+
+    //Update temperature display every second
+    //Infinite loop
+    while(1) {
+        uint16_t  raw = adc_read(); //Define a variable to store the raw output value from the adc
+
+        //Do the conversion
+        const float conversion = 3.3f / (1<<12);
+        float voltage = raw * conversion; // convert raw value to voltage
+        float temperature = 27 - (voltage - 0.706) / 0.001721; // convert voltage to temperature value
+
+        char strArray[25];
+        sprintf(strArray, "Temperature: %d", (int) temperature); //store output on char buffer
+
+        ST7735_FillScreen(ST7735_BLACK);//set screen color
+        ST7735_WriteString(0, 0, strArray, Font_16x26, ST7735_GREEN, ST7735_BLACK);//display temperature on screen
+
+        //can also use any other function from the library to display the temperature differently
+
+        //wait 1 sec
+        sleep_ms(1000);
+    }