1+ // Licensed to the .NET Foundation under one or more agreements.
2+ // The .NET Foundation licenses this file to you under the MIT license.
3+
4+ using System ;
5+ using System . Device ;
6+ using System . Device . Gpio ;
7+ using System . Device . Model ;
8+ using Iot . Device . Common ;
9+
10+ namespace Iot . Device . Rtc
11+ {
12+ /// <summary>
13+ /// Realtime Clock Ds1302.
14+ /// </summary>
15+ [ Interface ( "Realtime Clock Ds1302" ) ]
16+ public class Ds1302 : RtcBase
17+ {
18+ private readonly GpioPin _clockPin ;
19+ private readonly GpioPin _communicationEnabledPin ;
20+ private readonly GpioPin _dataPin ;
21+ private readonly byte enableWrite = 0b1000_0000 ;
22+ private readonly byte disableWrite = 0b0000_0000 ;
23+ private readonly byte enableWriteOrRead = 0b1000_0001 ;
24+ private readonly bool _shouldDispose ;
25+ private PinMode _currentDataPinDirection ;
26+ private GpioController _controller ;
27+
28+ /// <summary>
29+ /// Initializes a new instance of the <see cref="Ds1302"/> class.
30+ /// </summary>
31+ /// <param name="clockPin">Clock pin number.</param>
32+ /// <param name="dataPin">Data pin number.</param>
33+ /// <param name="communicationEnabledPin">Communication enabled pin number.</param>
34+ /// <param name="controller">Gpio controller.</param>
35+ /// <param name="shouldDispose">True to dispose the Gpio Controller.</param>
36+ /// <exception cref="ArgumentNullException">When pin numbers are not valid.</exception>
37+ public Ds1302 ( int clockPin , int dataPin , int communicationEnabledPin , GpioController ? controller = null , bool shouldDispose = true )
38+ {
39+ _controller = controller ?? new GpioController ( ) ;
40+ _shouldDispose = shouldDispose || controller is null ;
41+
42+ if ( clockPin < 0 || dataPin < 0 || communicationEnabledPin < 0 )
43+ {
44+ throw new ArgumentOutOfRangeException ( ) ;
45+ }
46+
47+ _clockPin = _controller . OpenPin ( clockPin , PinMode . Output ) ;
48+ _communicationEnabledPin = _controller . OpenPin ( communicationEnabledPin , PinMode . Output ) ;
49+ _dataPin = _controller . OpenPin ( dataPin , PinMode . Input ) ;
50+
51+ _communicationEnabledPin . Write ( PinValue . Low ) ;
52+ _clockPin . Write ( PinValue . Low ) ;
53+ }
54+
55+ /// <summary>
56+ /// Checks if the clock is halted.
57+ /// </summary>
58+ /// <returns><b>true</b> when clock is halted, else <b>false</b></returns>
59+ public bool IsHalted ( )
60+ {
61+ PrepareRead ( Ds1302Registers . REG_SECONDS ) ;
62+ byte seconds = ReadByte ( ) ;
63+ EndTransmission ( ) ;
64+ return ( byte ) ( seconds & enableWrite ) > 0 ;
65+ }
66+
67+ /// <summary>
68+ /// Halts the clock.
69+ /// </summary>
70+ public void Halt ( )
71+ {
72+ PrepareWrite ( Ds1302Registers . REG_SECONDS ) ;
73+ WriteByte ( enableWrite ) ;
74+ EndTransmission ( ) ;
75+ }
76+
77+ /// <summary>
78+ /// Read time from the device.
79+ /// </summary>
80+ /// <returns>Time from the device.</returns>
81+ protected override DateTime ReadTime ( )
82+ {
83+ PrepareRead ( Ds1302Registers . REG_BURST ) ;
84+ var seconds = NumberHelper . Bcd2Dec ( ( byte ) ( ReadByte ( ) & 0b0111_1111 ) ) ;
85+ var minutes = NumberHelper . Bcd2Dec ( ( byte ) ( ReadByte ( ) & 0b0111_1111 ) ) ;
86+ var hours = NumberHelper . Bcd2Dec ( ( byte ) ( ReadByte ( ) & 0b0011_1111 ) ) ;
87+ var days = NumberHelper . Bcd2Dec ( ( byte ) ( ReadByte ( ) & 0b0011_1111 ) ) ;
88+ var months = NumberHelper . Bcd2Dec ( ( byte ) ( ReadByte ( ) & 0b0001_1111 ) ) ;
89+ var dayOfWeek = NumberHelper . Bcd2Dec ( ( byte ) ( ReadByte ( ) & 0b0000_0111 ) ) ;
90+ var years = NumberHelper . Bcd2Dec ( ( byte ) ( ReadByte ( ) & 0b0111_1111 ) ) ;
91+
92+ EndTransmission ( ) ;
93+
94+ return new DateTime ( 2000 + years , months , days , hours , minutes , seconds , 0 ) ;
95+ }
96+
97+ /// <summary>
98+ /// Sets date and time.
99+ /// </summary>
100+ /// <param name="time">Date and time.</param>
101+ protected override void SetTime ( DateTime time )
102+ {
103+ PrepareWrite ( Ds1302Registers . REG_WP ) ;
104+ WriteByte ( disableWrite ) ;
105+ EndTransmission ( ) ;
106+
107+ PrepareWrite ( Ds1302Registers . REG_BURST ) ;
108+ WriteByte ( NumberHelper . Dec2Bcd ( time . Second ) ) ;
109+ WriteByte ( NumberHelper . Dec2Bcd ( time . Minute ) ) ;
110+ WriteByte ( NumberHelper . Dec2Bcd ( time . Hour ) ) ;
111+ WriteByte ( NumberHelper . Dec2Bcd ( time . Day ) ) ;
112+ WriteByte ( NumberHelper . Dec2Bcd ( time . Month ) ) ;
113+ WriteByte ( NumberHelper . Dec2Bcd ( ( int ) time . DayOfWeek ) ) ;
114+ WriteByte ( NumberHelper . Dec2Bcd ( time . Year - 2000 ) ) ;
115+
116+ WriteByte ( enableWrite ) ;
117+ EndTransmission ( ) ;
118+ }
119+
120+ /// <summary>
121+ /// <inheritdoc/>
122+ /// </summary>
123+ /// <param name="disposing">True to release both managed and unmanaged resources; false to release only unmanaged resources.</param>
124+ protected override void Dispose ( bool disposing )
125+ {
126+ _dataPin ? . Dispose ( ) ;
127+ _clockPin ? . Dispose ( ) ;
128+ _communicationEnabledPin ? . Dispose ( ) ;
129+ if ( _shouldDispose )
130+ {
131+ _controller ? . Dispose ( ) ;
132+ _controller = null ;
133+ }
134+ }
135+
136+ private byte ReadByte ( )
137+ {
138+ byte readValue = 0 ;
139+ for ( byte i = 0 ; i < 8 ; i ++ )
140+ {
141+ if ( _dataPin . Read ( ) == PinValue . High )
142+ {
143+ readValue |= ( byte ) ( 0x01 << i ) ;
144+ }
145+
146+ MoveToNextBit ( ) ;
147+ }
148+
149+ return readValue ;
150+ }
151+
152+ private void PrepareRead ( Ds1302Registers ds1302Register )
153+ {
154+ SetDirectionOfDataPin ( PinMode . Output ) ;
155+ _communicationEnabledPin . Write ( PinValue . High ) ;
156+ WriteByte ( ( byte ) ( enableWriteOrRead | ( byte ) ds1302Register ) ) ;
157+ SetDirectionOfDataPin ( PinMode . Input ) ;
158+ }
159+
160+ private void PrepareWrite ( Ds1302Registers ds1302Register )
161+ {
162+ SetDirectionOfDataPin ( PinMode . Output ) ;
163+ _communicationEnabledPin . Write ( PinValue . High ) ;
164+ WriteByte ( ( byte ) ( enableWrite | ( byte ) ds1302Register ) ) ;
165+ }
166+
167+ private void EndTransmission ( )
168+ {
169+ _communicationEnabledPin . Write ( PinValue . Low ) ;
170+ }
171+
172+ private void SetDirectionOfDataPin ( PinMode direction )
173+ {
174+ if ( _currentDataPinDirection != direction )
175+ {
176+ _currentDataPinDirection = direction ;
177+ _dataPin . SetPinMode ( _currentDataPinDirection ) ;
178+ }
179+ }
180+
181+ private void WriteByte ( byte register )
182+ {
183+ for ( int i = 0 ; i < 8 ; i ++ )
184+ {
185+ _dataPin . Write ( ( register & 0x01 ) > 0 ? PinValue . High : PinValue . Low ) ;
186+ MoveToNextBit ( ) ;
187+ register >>= 1 ;
188+ }
189+ }
190+
191+ private void MoveToNextBit ( )
192+ {
193+ _clockPin . Write ( PinValue . High ) ;
194+ DelayHelper . DelayMicroseconds ( 1 , true ) ;
195+ _clockPin . Write ( PinValue . Low ) ;
196+ DelayHelper . DelayMicroseconds ( 1 , true ) ;
197+ }
198+ }
199+ }
0 commit comments