import serial
import time
import math
#
def readtemp(): # command write to read two bytes from tmp1075, into internal memory
    x = b'\x90\xeb\x02\x02\x06\x00\x48\x00\x06\x00'  #command to read chip
    ser.write(x)
    time.sleep(0.1)
    x = b'\x90\xeb\x01\x00\x08\x00'  #command to read data from registers
    ser.write(x)
    time.sleep(0.1)
#    
def readtime(): # command write to read first eight bytes of 3231 into internal registers
    x = b'\x90\xeb\x02\x02\x0e\x00\x68\x00\x0e\x00'  #command to read chip
    ser.write(x)
    time.sleep(0.1)
    x = b'\x90\xeb\x04\x00\x10\x00'  #command to read data from registers
    ser.write(x)
    time.sleep(0.1)
#    
def writetime(): # write discrete time set in string
    x = b'\x90\xeb\x06\x02\x0e\x00\x68\x00\x1d\x00' #header to write
    x = x + b'\x00\x30\x20\x01\x03\x03\x24\x00'  #time:20:30, sunday, march 3, 24
    ser.write(x)
    time.sleep(0.1)    
#
# configure the serial connections 
ser = serial.Serial()
ser.baudrate = 115200
ser.port = 'COM8'
ser.open()
#
print(ser.name)             # check which port was really used
print(ser.is_open)
#
#writetime()
#
while True:
    y = bytearray(14)
    readtime()
    y = ser.read(14)
    time_sec = (y[6]&0x0f) + ((y[6]>>4) * 10)
    time_min = (y[7]&0x0f) + ((y[7]>>4) * 10)
    time_hour = (y[8]&0x0f) + ((y[8]>>4) * 10)
    print ('Time:',time_hour,':',time_min,':',time_sec)
    readtemp()
    y = ser.read(8)
    temp = y[6] + ((y[7]>>4)/16)
    if temp >= 128: #handle negative temperatures
        temp = temp-256
    temp = temp*1.8+32 #convert to fahrenheit
    print ('Temp:',temp)
    time.sleep(1)
    
#    
ser.close()