# MAX17048.py

SMBUS = True

if SMBUS:
    import smbus
else:
    from smbus2 import SMBus

import time


class My_MAX17048:
    
    def __init__(self):
    
        # MAX17048 registers 
        # NAME	 ADDRESS         PURPOSE/CONTENTS
        self.VCell = 0x02	 # Cell voltage for a single cell
        self.SOC = 0x04 	 # Reported state of charge in mAhrs
        self.MODE = 0x06         # Initiates quick-start, reports hibernation mode, enables sleep mode
        self.Version = 0x08      # IC production version     
        self.HIBRT = 0x0A	 # Controls trhesholds for entering and leaving hiberation
        self.Config = 0x0C	 # Compensation to optimize performance
        self.VALRT = 0x14	 # VCELL range for alerts
        self.CRATE = 0x16	 # charge/discharge rate of battery
        self.Vreset_ID = 0x18    # VCELL threshold for reset
        self.ChipID = 0x19       # Chip ID
        self.Status = 0x1A       # shows alerts
        self.Table_start = 0x40  # Battery config
        self.Table_end = 0x7F    # Battery config
        self.CMD = 0xFE          # Send POR command
        
        if SMBUS:
            self.i2cbus = smbus.SMBus(1)
        else:
            self.i2cbus = SMBus(1)    # Create a new I2C bus on port 1: pins 3 (SDA) and 5 (SCL)
        
        self.i2caddress = 0x36    # address of MAX17048
            
        # Status register masks
        # These bits are set only when they cause an alert (e.g., if CONFIG.ALSC = 0, then SC is never set).
        # Reset Indicator:
        # RI (reset indicator) is set when the device powers up. Any time this bit is set, the IC is not configured, so the
        # model should be loaded and the bit should be cleared.
        self.RI = 0x01FF
        
        # VH (voltage high) is set when VCELL has been above ALRT.VALRTMAX.
        self.VH = 0x02FF
        
        # VL (voltage low) is set when VCELL has been below ALRT.VALRTMIN.
        self.VL = 0x4FF
        
        # VR (voltage reset) is set after the device has been reset if EnVr is set.
        self.VR = 0x08FF
        
        # HD (SOC low) is set when SOC crosses the value in CONFIG.ATHD.
        self.HD = 0x10FF
        
        # SC (1% SOC change) is set when SOC changes by at least 1% if CONFIG.ALSC is set.
        self.SC = 0x20FF
        
        # Enable or Disable VRESET Alert:
        # EnVr (enable voltage reset alert) when set to 1 asserts the ALRT pin when a voltage-reset event occurs under
        # the conditions described by the VRESET/ ID register.
        self.ENVR = 0x40FF        
       
    def read_Status(self):
        s = self._read_register(self.Status)
        status = self._decode_status_register(s)
        return status

    def read_VCell(self):
        value = self._read_register(self.VCell)
        return value, (value * 78.125) / 1000000

    def read_SOC(self):
        value = self._read_register(self.SOC)
        return value, int(value) / 256
    
    def read_Chip_ID(self):
        value = self._read_register(self.ChipID)
        return value    

    def read_Version(self):
        return self._read_register(self.Version)

    def read_Config(self):
        return self._read_register(self.Config)

    def read_VALRT(self):
        return self._read_register(self.VALRT)

    def read_CRATE(self):
        value = self._read_register(self.CRATE)
        return value * 0.208

    def read_Vreset_ID(self):
        return self._read_register(self.Vreset_ID)

    def read_Status(self):
        return self._read_register(self.Status)

    def read_CMD(self):
        return self._read_register(self.CMD)
    
    def _read_register(self, register):
        if SMBUS:
            d = self.i2cbus.read_i2c_block_data(self.i2caddress, register, 2)
            data = d[0] * 256 + d[1]
        else:
            data = self.i2cbus.read_word_data(self.i2caddress, register)
        return data
    
    def _write_register(self, register, data):
        self.i2cbus.write_word_data(self.i2caddress, register, data)
    
    def _decode_status_register(self, data):       
        status = {
            "RI": bool(data & self.RI),
            "VH": bool(data & self.VH),
            "VL": bool(data & self.VL),
            "VR": bool(data & self.VR),
            "HD": bool(data & self.HD),
            "SC": bool(data & self.SC),
            "ENVR": bool(data & self.ENVR),
        }
        return status