# RTC_DS1302 - Python Hardware Programming Education Project For Raspberry Pi
# Copyright (C) 2015 Jason Birch
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#/****************************************************************************/
#/* RTC_DS1302                                                               */
#/* ------------------------------------------------------------------------ */
#/* V1.00 - 2015-08-26 - Jason Birch                                         */
#/* ------------------------------------------------------------------------ */
#/* Class to handle controlling a Real Time Clock IC DS1302.                 */
#/****************************************************************************/

import time
import operator
import RPi.GPIO


class RTC_DS1302:
#  RTC_DS1302_SCLK = 2
   RTC_DS1302_SCLK = 27
#   RTC_DS1302_CE = 3
   RTC_DS1302_CE = 17
#   RTC_DS1302_IO = 4
   RTC_DS1302_IO = 18

   CLK_PERIOD = 0.00001

   DOW = [ "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday" ]


   def __init__(self):
# Turn off GPIO warnings.
      RPi.GPIO.setwarnings(False)
# Configure Raspberry Pi GPIO interfaces.
      RPi.GPIO.setmode(RPi.GPIO.BCM)
# Initiate DS1302 communication.
      self.InitiateDS1302()
# Make sure write protect is turned off.
      self.WriteByte(int("10001110", 2))
      self.WriteByte(int("00000000", 2))
# Make sure trickle charge mode is turned off.
      self.WriteByte(int("10010000", 2))
      self.WriteByte(int("00000000", 2))
# End DS1302 communication.
      self.EndDS1302()


#/*************************************************/
#/* Close Raspberry Pi GPIO use before finishing. */
#/*************************************************/
   def CloseGPIO(self):
      RPi.GPIO.cleanup()


#/********************************************/
#/* Start a transaction with the DS1302 RTC. */
#/********************************************/
   def InitiateDS1302(self):
      RPi.GPIO.setup(self.RTC_DS1302_SCLK, RPi.GPIO.OUT, initial=0)
      RPi.GPIO.setup(self.RTC_DS1302_CE, RPi.GPIO.OUT, initial=0)
      RPi.GPIO.setup(self.RTC_DS1302_IO, RPi.GPIO.OUT, initial=0)
      RPi.GPIO.output(self.RTC_DS1302_SCLK, 0)
      RPi.GPIO.output(self.RTC_DS1302_IO, 0)
      time.sleep(self.CLK_PERIOD)
      RPi.GPIO.output(self.RTC_DS1302_CE, 1)


#/***********************************************/
#/* Complete a transaction with the DS1302 RTC. */
#/***********************************************/
   def EndDS1302(self):
      RPi.GPIO.setup(self.RTC_DS1302_SCLK, RPi.GPIO.OUT, initial=0)
      RPi.GPIO.setup(self.RTC_DS1302_CE, RPi.GPIO.OUT, initial=0)
      RPi.GPIO.setup(self.RTC_DS1302_IO, RPi.GPIO.OUT, initial=0)
      RPi.GPIO.output(self.RTC_DS1302_SCLK, 0)
      RPi.GPIO.output(self.RTC_DS1302_IO, 0)
      time.sleep(self.CLK_PERIOD)
      RPi.GPIO.output(self.RTC_DS1302_CE, 0)


#/*******************************************/
#/* Write a byte of data to the DS1302 RTC. */
#/*******************************************/
   def WriteByte(self, Byte):
      for Count in range(8):
         time.sleep(self.CLK_PERIOD)
         RPi.GPIO.output(self.RTC_DS1302_SCLK, 0)

         Bit = operator.mod(Byte, 2)
         Byte = operator.div(Byte, 2)
         time.sleep(self.CLK_PERIOD)
         RPi.GPIO.output(self.RTC_DS1302_IO, Bit)

         time.sleep(self.CLK_PERIOD)
         RPi.GPIO.output(self.RTC_DS1302_SCLK, 1)
      

#/******************************************/
#/* Read a byte of data to the DS1302 RTC. */
#/******************************************/
   def ReadByte(self):
      RPi.GPIO.setup(self.RTC_DS1302_IO, RPi.GPIO.IN, pull_up_down=RPi.GPIO.PUD_DOWN)

      Byte = 0
      for Count in range(8):
         time.sleep(self.CLK_PERIOD)
         RPi.GPIO.output(self.RTC_DS1302_SCLK, 1)

         time.sleep(self.CLK_PERIOD)
         RPi.GPIO.output(self.RTC_DS1302_SCLK, 0)
         
         time.sleep(self.CLK_PERIOD)
         Bit = RPi.GPIO.input(self.RTC_DS1302_IO)
         Byte |= ((2 ** Count) * Bit)

      return Byte


#/***********************************/
#/* Write a message to the RTC RAM. */
#/***********************************/
   def WriteRAM(self, Data):
# Initiate DS1302 communication.
      self.InitiateDS1302()
# Write address byte.
      self.WriteByte(int("11111110", 2))
# Write data bytes.
      for Count in range(len(Data)):
         self.WriteByte(ord(Data[Count:Count + 1]))
      for Count in range(31 - len(Data)):
         self.WriteByte(ord(" "))
# End DS1302 communication.
      self.EndDS1302()


#/**********************************/
#/* Read message from the RTC RAM. */
#/**********************************/
   def ReadRAM(self):
# Initiate DS1302 communication.
      self.InitiateDS1302()
# Write address byte.
      self.WriteByte(int("11111111", 2))
# Read data bytes.
      Data = ""
      for Count in range(31):
         Byte = self.ReadByte()
         Data += chr(Byte)
# End DS1302 communication.
      self.EndDS1302()
      return Data


#/***********************************/
#/* Write date and time to the RTC. */
#/***********************************/
   def WriteDateTime(self, Year, Month, Day, DayOfWeek, Hour, Minute, Second):
# Initiate DS1302 communication.
      self.InitiateDS1302()
# Write address byte.
      self.WriteByte(int("10111110", 2))
# Write seconds data.
      self.WriteByte(operator.mod(Second, 10) | operator.div(Second, 10) * 16)
# Write minute data.
      self.WriteByte(operator.mod(Minute, 10) | operator.div(Minute, 10) * 16)
# Write hour data.
      self.WriteByte(operator.mod(Hour, 10) | operator.div(Hour, 10) * 16)
# Write day data.
      self.WriteByte(operator.mod(Day, 10) | operator.div(Day, 10) * 16)
# Write month data.
      self.WriteByte(operator.mod(Month, 10) | operator.div(Month, 10) * 16)
# Write day of week data.
      self.WriteByte(operator.mod(DayOfWeek, 10) | operator.div(DayOfWeek, 10) * 16)
# Write year of week data.
      self.WriteByte(operator.mod(Year, 10) | operator.div(Year, 10) * 16)
# Make sure write protect is turned off.
      self.WriteByte(int("00000000", 2))
# Make sure trickle charge mode is turned off.
      self.WriteByte(int("00000000", 2))
# End DS1302 communication.
      self.EndDS1302()


#/*************************************/
#/* Read date and time from the RTC. */
#/*************************************/
   def ReadDateTime(self, DateTime):
# Initiate DS1302 communication.
      self.InitiateDS1302()
# Write address byte.
      self.WriteByte(int("10111111", 2))
# Read date and time data.
      Data = ""

      Byte = self.ReadByte()
      DateTime["Second"] = operator.mod(Byte, 16) + operator.div(Byte, 16) * 10
      Byte = self.ReadByte()
      DateTime["Minute"] = operator.mod(Byte, 16) + operator.div(Byte, 16) * 10
      Byte = self.ReadByte()
      DateTime["Hour"] = operator.mod(Byte, 16) + operator.div(Byte, 16) * 10
      Byte = self.ReadByte()
      DateTime["Day"] = operator.mod(Byte, 16) + operator.div(Byte, 16) * 10
      Byte = self.ReadByte()
      DateTime["Month"] = operator.mod(Byte, 16) + operator.div(Byte, 16) * 10
      Byte = self.ReadByte()
      DateTime["DayOfWeek"] = (operator.mod(Byte, 16) + operator.div(Byte, 16) * 10) - 1
      Byte = self.ReadByte()
      DateTime["Year"] = operator.mod(Byte, 16) + operator.div(Byte, 16) * 10

      Data = self.DOW[DateTime["DayOfWeek"]] + " " + format(DateTime["Year"] + 2000, "04d") + "-" + format(DateTime["Month"], "02d") + "-" + format(DateTime["Day"], "02d")
      Data += " " + format(DateTime["Hour"], "02d") + ":" + format(DateTime["Minute"], "02d") + ":" + format(DateTime["Second"], "02d")

# End DS1302 communication.
      self.EndDS1302()
      return Data