1+ /* !
2+ * @file WipperSnapper_I2C_Driver_DS2484.h
3+ *
4+ * Device driver the DS2484 I2C OneWire converter (hosting a DS18b20).
5+ *
6+ * Adafruit invests time and resources providing this open source code,
7+ * please support Adafruit and open-source hardware by purchasing
8+ * products from Adafruit!
9+ *
10+ * Copyright (c) Tyeth Gundry 2024 for Adafruit Industries.
11+ *
12+ * MIT license, all text here must be included in any redistribution.
13+ *
14+ */
15+
16+ #ifndef WipperSnapper_I2C_Driver_DS2484_H
17+ #define WipperSnapper_I2C_Driver_DS2484_H
18+
19+ #define DS18B20_FAMILY_CODE 0x28 // /< DS18B20 family code
20+ #define DS18B20_CMD_CONVERT_T 0x44 // /< Convert T command
21+ #define DS18B20_CMD_MATCH_ROM 0x55 // /< Match ROM command
22+ #define DS18B20_CMD_READ_SCRATCHPAD 0xBE // /< Read Scratchpad command
23+
24+ #include " WipperSnapper_I2C_Driver.h"
25+ #include < Adafruit_DS248x.h>
26+
27+ /* *************************************************************************/
28+ /* !
29+ @brief Class that provides a sensor driver for the DS2484 I2C OneWire
30+ converter hosting a DS18b20 temperature sensor.
31+ */
32+ /* *************************************************************************/
33+ class WipperSnapper_I2C_Driver_DS2484 : public WipperSnapper_I2C_Driver {
34+
35+ public:
36+ /* ******************************************************************************/
37+ /* !
38+ @brief Constructor for a DS2484 sensor.
39+ @param i2c
40+ The I2C interface.
41+ @param sensorAddress
42+ 7-bit device address.
43+ */
44+ /* ******************************************************************************/
45+ WipperSnapper_I2C_Driver_DS2484 (TwoWire *i2c, uint16_t sensorAddress)
46+ : WipperSnapper_I2C_Driver(i2c, sensorAddress) {
47+ _i2c = i2c;
48+ _sensorAddress = sensorAddress;
49+ }
50+
51+ /* ******************************************************************************/
52+ /* !
53+ @brief Destructor for an DS2484 sensor.
54+ */
55+ /* ******************************************************************************/
56+ ~WipperSnapper_I2C_Driver_DS2484 () { delete _ds2484; }
57+
58+ /* ******************************************************************************/
59+ /* !
60+ @brief Initializes the DS2484 sensor and begins I2C.
61+ @returns True if initialized successfully, False otherwise.
62+ */
63+ /* ******************************************************************************/
64+ bool begin () {
65+ // initialize DS2484
66+ _ds2484 = new Adafruit_DS248x ();
67+ if (!_ds2484->begin (_i2c, (uint8_t )_sensorAddress)) {
68+ WS_DEBUG_PRINTLN (" Could not find DS2484"
69+ return false ;
70+ }
71+
72+ // check bus is okay
73+ if (!_ds2484->OneWireReset ()) {
74+ WS_DEBUG_PRINTLN (" Failed to do a OneWire bus reset"
75+ if (_ds2484->shortDetected ()) {
76+ WS_DEBUG_PRINTLN (" \t Short detected"
77+ }
78+ if (!_ds2484->presencePulseDetected ()) {
79+ WS_DEBUG_PRINTLN (" \t No presense pulse"
80+ }
81+ return false ;
82+ }
83+
84+ // locate first DS18B20
85+ bool found_device = false ;
86+ _ds2484->OneWireReset ();
87+ _ds2484->OneWireSearchReset ();
88+ while (!found_device && _ds2484->OneWireSearch (_rom)) {
89+ if (_rom[0 ] == DS18B20_FAMILY_CODE) {
90+ found_device = true ;
91+ } else {
92+ WS_DEBUG_PRINT (" Found unwanted device with family code: 0x"
93+ WS_DEBUG_PRINTHEX (_rom[0 ]);
94+ WS_DEBUG_PRINTLN (" expected 0x28" // DS18B20_FAMILY_CODE
95+ }
96+ }
97+
98+ if (!found_device) {
99+ WS_DEBUG_PRINTLN (" Could not find DS18B20 attached to DS2484"
100+ return false ;
101+ }
102+
103+ WS_DEBUG_PRINTLN (" DS2484 found"
104+ return true ;
105+ }
106+
107+ /* ******************************************************************************/
108+ /* !
109+ @brief Processes a temperature event.
110+ @param tempEvent
111+ Pointer to an Adafruit_Sensor event.
112+ @returns True if the temperature was obtained successfully, False
113+ otherwise.
114+ */
115+ bool processTemperatureEvent (sensors_event_t *tempEvent) {
116+ if (!_ds2484->OneWireReset ()) {
117+ WS_DEBUG_PRINTLN (" Failed to do a OneWire bus reset"
118+ return false ;
119+ }
120+ if (!_ds2484->presencePulseDetected ()) {
121+ tempEvent->temperature = NAN;
122+ return true ;
123+ }
124+
125+ _ds2484->OneWireWriteByte (DS18B20_CMD_MATCH_ROM); // Match ROM command
126+ for (int i = 0 ; i < 8 ; i++) {
127+ _ds2484->OneWireWriteByte (_rom[i]);
128+ }
129+
130+ // Start temperature conversion
131+ _ds2484->OneWireWriteByte (DS18B20_CMD_CONVERT_T); // Convert T command
132+ delay (750 ); // Wait for conversion (750ms for maximum precision)
133+
134+ // Read scratchpad
135+ if (!_ds2484->OneWireReset ()) {
136+ WS_DEBUG_PRINTLN (
137+ " Failed to do a OneWire bus reset after starting temp conversion"
138+ return false ;
139+ }
140+ _ds2484->OneWireWriteByte (DS18B20_CMD_MATCH_ROM); // Match ROM command
141+ for (int i = 0 ; i < 8 ; i++) {
142+ _ds2484->OneWireWriteByte (_rom[i]);
143+ }
144+ _ds2484->OneWireWriteByte (
145+ DS18B20_CMD_READ_SCRATCHPAD); // Read Scratchpad command
146+
147+ uint8_t data[9 ];
148+ for (int i = 0 ; i < sizeof (data) / sizeof (data[0 ]); i++) {
149+ _ds2484->OneWireReadByte (&data[i]);
150+ }
151+
152+ // Calculate temperature
153+ int16_t raw = (data[1 ] << 8 ) | data[0 ];
154+ tempEvent->temperature = (float )raw / 16.0 ;
155+ return true ;
156+ }
157+
158+ /* ******************************************************************************/
159+ /* !
160+ @brief Gets the DS2484's current temperature.
161+ @param tempEvent
162+ Pointer to an Adafruit_Sensor event.
163+ @returns True if the temperature was obtained successfully, False
164+ otherwise.
165+ */
166+ /* ******************************************************************************/
167+ bool getEventAmbientTemp (sensors_event_t *tempEvent) {
168+ return processTemperatureEvent (tempEvent);
169+ }
170+
171+ protected:
172+ Adafruit_DS248x *_ds2484; // /< DS2484 driver object
173+ uint8_t _rom[8 ]; // /< DS18B20 ROM
174+ };
175+
176+ #endif // WipperSnapper_I2C_Driver_DS2484
0 commit comments