# Experiment D: I2C & SPI Communication 
# Uses MPU-6050 (I2C) and 74HC595 (SPI)
import machine
import utime
import ustruct

# --- 1. INIT I2C for MPU-6050 ---
i2c = machine.I2C(0, scl=machine.Pin(1), sda=machine.Pin(0), freq=400000)
MPU6050_ADDR = 0x68  # Default I2C address

# Wake up the MPU-6050 (it starts in sleep mode)
try:
    i2c.writeto_mem(MPU6050_ADDR, 0x6B, b'\x00')
    print("✅ MPU-6050 I2C Initialized")
except Exception as e:
    print(f"❌ I2C Init Error: {e}")

# --- 2. INIT SPI for 74HC595 ---

spi = machine.SPI(0,
                  baudrate=100000,
                  polarity=0,
                  phase=0,
                  sck=machine.Pin(2),   
                  mosi=machine.Pin(7),  
                  miso=machine.Pin(4)) 


cs = machine.Pin(3, machine.Pin.OUT)   
cs.value(1)  

def read_mpu6050_temp():
    """Read the temperature from MPU-6050's internal sensor."""
    try:
        # Temperature register address is 0x41 (high byte) and 0x42 (low byte)
        data = i2c.readfrom_mem(MPU6050_ADDR, 0x41, 2)
        # Convert raw data (big-endian signed short)
        raw_temp = ustruct.unpack('>h', data)[0]
        # Formula from datasheet: Temp = (raw_temp / 340.0) + 36.53
        temp_c = (raw_temp / 340.0) + 36.53
        return temp_c
    except Exception as e:
        print(f"⚠️ I2C Read Error: {e}")
        return 25.0  # Default fallback

print("🎯 Experiment D: I2C (MPU-6050) + SPI (74HC595)")
print("📡 Reading Temp from MPU-6050, controlling LEDs via 74HC595")
print("-" * 50)

patterns = [
    0b00000001, 0b00000011, 0b00000111, 0b00001111,
    0b00011111, 0b00111111, 0b01111111, 0b11111111,
    0b01111111, 0b00111111, 0b00011111, 0b00001111,
    0b00000111, 0b00000011
]
pattern_index = 0

try:
    while True:
        # --- A. READ TEMPERATURE via I2C ---
        temp_c = read_mpu6050_temp()
        
        # --- B. DECIDE ACTION based on temperature ---
        
        if temp_c > 30.0:
            delay = 100
            max_pattern = 0b11111111  
        elif temp_c < 20.0:
            delay = 500
            max_pattern = 0b00000001  
        else:
            delay = 300
            max_pattern = 0b00001111  
        
        
        current_pattern = patterns[pattern_index] & max_pattern
        
        cs.value(0)
        spi.write(bytes([current_pattern]))
        cs.value(1)
        
        pattern_index = (pattern_index + 1) % len(patterns)
        print(f"🌡️ Temp: {temp_c:5.1f}°C | LEDs: {current_pattern:08b}")
        
        utime.sleep_ms(delay)
        
except KeyboardInterrupt:
    # Cleanup: Turn off all LEDs on exit
    cs.value(0)
    spi.write(bytes([0b00000000]))
    cs.value(1)
    print("\n🛑 Experiment D safely stopped. LEDs off.")