from machine import Pin, ADC, Timer
import time

# SEGMENTS = GP0 to GP7 (A–DP)
segment_pins = [Pin(i, Pin.OUT) for i in range(8)]
# DIGITS = GP11 to GP8 (left to right)
digit_pins = [Pin(i, Pin.OUT) for i in range(11, 7, -1)]

adc = ADC(Pin(26))
button = Pin(16, Pin.IN, Pin.PULL_UP)

voltage_read = 0.0
last_press_time = 0

digit_codes = {
    0: [1, 1, 1, 1, 1, 1, 0],
    1: [0, 1, 1, 0, 0, 0, 0],
    2: [1, 1, 0, 1, 1, 0, 1],
    3: [1, 1, 1, 1, 0, 0, 1],
    4: [0, 1, 1, 0, 0, 1, 1],
    5: [1, 0, 1, 1, 0, 1, 1],
    6: [1, 0, 1, 1, 1, 1, 1],
    7: [1, 1, 1, 0, 0, 0, 0],
    8: [1, 1, 1, 1, 1, 1, 1],
    9: [1, 1, 1, 1, 0, 1, 1]
}

def voltage_to_digits(v):
    v = max(0.0, min(v, 9.999))
    val = int(v * 1000)
    return [val // 1000, (val % 1000) // 100, (val % 100) // 10, val % 10]

def show_digit(val, pos, dot=False):
    code = digit_codes.get(val, [0]*7)
    for i in range(7):
        segment_pins[i].value(code[i])
    segment_pins[7].value(1 if dot else 0)
    for i in range(4):
        digit_pins[i].value(1)
    digit_pins[pos].value(0)
    time.sleep_ms(2)
    digit_pins[pos].value(1)

def refresh_display(timer):
    digits = voltage_to_digits(voltage_read)
    for i in range(4):
        dp = True if i == 0 else False  # Decimal after 1st digit
        show_digit(digits[i], i, dot=dp)

def handle_button(pin):
    global voltage_read, last_press_time
    now = time.ticks_ms()
    if time.ticks_diff(now, last_press_time) > 200:
        last_press_time = now
        voltage_read = round((adc.read_u16() / 65535) * 3.3, 3)
        print("Voltage:", voltage_read)

# Attach interrupt to button
button.irq(trigger=Pin.IRQ_FALLING, handler=handle_button)

# Start display timer
timer = Timer()
timer.init(freq=250, mode=Timer.PERIODIC, callback=refresh_display)

# Main loop (empty, because interrupts & timers handle everything)
print("Voltmeter running...")
while True:
    time.sleep(1)