tinyTemp

ATtiny85 firmware that reads temperature from an analog sensor on ADC channel 2 (1.1 V ref), averages 25 samples, converts to °C and °F, and displays on a 0.96" 128×64 SSD1306 OLED. Display alternates °F (3 s) and °C (3 s) and shows "TOO HOT!!!" above 70 °F. ECE 304 project; all logic on the MCU, no host PC. I2C to the OLED is bit-banged (ATtiny85 has no hardware I2C). Demonstrates embedded C: ADC, timing, PROGMEM, bit-banged I2C, and display driver integration on a resource-constrained MCU.

main() and ADC main() disables the watchdog, then calls adc_init(), OLED_init(), and OLED_clear(). The ADC uses internal 1.1 V ref and channel 2; 25 samples are summed via get_adc() (start conversion, wait for ADIF, read ADCL then ADCH for 10-bit value). Temperature is computed from the averaged reading with a linear formula to °C and then °F.

display_temp and main loop display_temp(value, unit) formats the value to one decimal and prints either " Deg C " or " Deg F " from PROGMEM. The main loop shows °F, and if above 70 °F prints "TOO HOT!!!" at a fixed position; waits 3 s; clears; shows °C with the same logic; then enables the watchdog (8 s) and spins in while(1).

tinyOLED.c driver SSD1306 driver: PROGMEM init sequence (multiplex, addressing, charge pump, display on), 5×8 font, and OLED_cursor / OLED_printC / OLED_printP for positioning and text. Bit-banged I2C on GPIO. Build: make for tinyTemp.c + tinyOLED.c; make flash uses avrdude and USBtinyISP to program the ATtiny85.