from machine import Pin, SPI
import time

# SPI0 pins on Raspberry Pi Pico
SCK  = Pin(18)
MOSI = Pin(19)
MISO = Pin(16)
CS   = Pin(17, Pin.OUT, value=1)

spi = SPI(0, baudrate=1_000_000, polarity=0, phase=0, bits=8, firstbit=SPI.MSB, sck=SCK, mosi=MOSI, miso=MISO)

def read_mcp3008(ch=0):
    """Read 10-bit value (0..1023) from MCP3008 channel ch."""
    if not (0 <= ch <= 7):
        raise ValueError("Channel must be 0..7")
    # MCP3008 protocol: start(1), single-ended(1), ch(3), then 10 data bits
    cmd = 0b11 << 6 | (ch & 0x07) << 3
    CS.value(0)
    buf = spi.readinto if False else None  # just to keep lints quiet
    resp = spi.read(3, write=bytes([1, cmd, 0]))  # send 0x01, cmd, 0x00
    CS.value(1)
    # resp[1] carries the top 2 data bits (bits 9..8 in its LSBs), resp[2] has bits 7..0
    value = ((resp[1] & 0x03) << 8) | resp[2]
    return value

def to_percent(raw):
    # map 0..1023 to 0..100%
    return int((raw * 100) / 1023)

def moisture_band(p):
    if p < 20: return "Very Dry"
    if p < 40: return "Dry"
    if p < 60: return "Optimal"
    if p < 80: return "Moist"
    return "Wet"

print("Reading MCP3008 CH0. Move the Soil Moisture slider on the custom chip.")
while True:
    raw = read_mcp3008(0)
    pct = to_percent(raw)
    print("Moisture raw:", raw, " -> ", pct, "%  |  ", moisture_band(pct))
    time.sleep(0.25)