# BH1750FVI MTreg change test

import smbus
import time
from decimal import Decimal, ROUND_HALF_UP

bus = smbus.SMBus(1)
addr = 0x23

def MTreg_set(mt, h_value, l_value):
    bus.write_byte(addr, h_value)
    bus.write_byte(addr, l_value)
    print('<MTreg = ' + str(mt) + '>')
    time.sleep(0.5)
    
def sensor_read(mt):
    luxRead = bus.read_i2c_block_data(addr, 0x10)
#    lx = int((luxRead[0]*256 + luxRead[1]) / 1.2 * (69 / mt))
    lx = ((luxRead[0] << 8) | luxRead[1]) / 1.2 * (69 / mt)
    print('{:.2f}'.format(lx))
    print('Illuminance: ' + str(Decimal(str(lx)).quantize(Decimal('0'), rounding=ROUND_HALF_UP)) + ' lux')
    time.sleep(0.5)

print('<H-Resolution mode>' + '\n')
bus.write_byte(addr, 0x10)
time.sleep(1)     # important setting (MIN=0.6)

# MTreg=69(default)
MTreg_set(69, 0x42, 0x65)
sensor_read(69)

# MTreg=31(min)
MTreg_set(31, 0x40, 0x7f)
sensor_read(31)

# MTreg=254(max)
MTreg_set(254, 0x47, 0x7e)
sensor_read(254)