from machine import I2C

from utime import sleep_ms

class aht20(object):

def __init__(self):

self.i2c = I2C(I2C.I2C0,I2C.STANDARD_MODE)

self.slave_addr = 0x38# AHT20 slave address

self.RESET_CMD = b'\xBA'# reset command

self.INIT_CMD = b'\xE1'# initialize command

self.MEASURE_CMD = b'\xAC\x33\x00'# measure command

def reset(self):

self.i2c.write(self.slave_addr,b'\x00',0,self.RESET_CMD,len(self.RESET_CMD))

sleep_ms(20)# wait 20ms

def init(self):

self.i2c.write(self.slave_addr,b'\x00',0,self.INIT_CMD,len(self.INIT_CMD))

def read(self):

# Send measurement cmd to trigger data acquirement.

self.i2c.write(self.slave_addr,b'\x00',0,self.MEASURE_CMD,len(self.MEASURE_CMD))

#read data

#wait for data ready (at least 80ms)

sleep_ms(80)

r_data = bytearray([0x00]*6)

self.i2c.read(self.slave_addr,b'\x00',0,r_data,6,80)

busy = 0#r_data[0]>>7

if not busy:

RH_reg_data = (r_data[1]<<12) | (r_data[2]<<4) | (r_data[3]>>4)

RH = RH_reg_data/(1<<20) * 100

temp_reg_data = ((r_data[3]&0x0F)<<16) | (r_data[4]<<8) | r_data[5]

temp = temp_reg_data/(1<<20) * 200 - 50

return RH,temp

else:

return ()

if __name__ == '__main__':

aht20_obj = aht20()

aht20_obj.init()

sleep_ms(1000)

while True:

res = aht20_obj.read()

if res:

print("RH: %.2f%%" % res[0])

print("Temp: %.2f" % res[1])

print("------------")

else:

print("read error")

sleep_ms(1000)