1DS2760(3) One-Wire File System DS2760(3)
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6 DS2781 - Stand-alone Fuel Gauge IC
7
9 Temperature Voltage Current Memory and Switch.
10 3D [.]XXXXXXXXXXXX[XX][/[ lock.[0-1|ALL] | memory |
11 pages/page.[0-1|ALL] | PIO | sensed | temperature | vbias | vis |
12 vis_avg | vis_offset | volt | volthours |
13 aef | chgtf | learnf | pmod | porf | sef | uven | uvf |
14 address | crc8 | id | locator | r_address | r_id | r_locator | type ]]
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16 Thermocouple
17 3D [.]XXXXXXXXXXXX[XX][/[ temperature | typeX/range_low |
18 typeX/range_high | typeX/temperature
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21 3D
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24 lock.[0-1|ALL]
25 read-write, yes-no
26 Lock either of the two eprom pages to prevent further writes. Appar‐
27 ently setting lock is permanent.
28
29 memory
30 read-write, binary
31 Access to the full 256 byte memory range. Much of this space is
32 reserved or special use. User space is the page area.
33 See the DATASHEET for a full memory map.
34
35 pages/pages.[0-1|ALL]
36 read-write, binary Two 16 byte areas of memory for user application.
37 The lock property can prevent further alteration.
38 NOTE that the page property is different from the common OWFS implemen‐
39 tation in that all of memory is not accessible.
40
41 PIO
42 write-only, yes-no
43 Controls the PIO pin allowing external switching.
44 Writing "1" turns the PIO pin on (conducting). Writing "0" makes the
45 pin non-conducting. The logical state of the voltage can be read with
46 the sensed property. This will reflect the current voltage at the pin,
47 not the value sent to PIO
48 Note also that PIO will also be altered by the power-status of the
49 DS2680 See the datasheet for details.
50
51 sensed
52 read-only, yes-no
53 The logical voltage at the PIO pin. Useful only if the PIO property is
54 set to "0" (non-conducting).
55 Value will be 0 or 1 depending on the voltage threshold.
56
57 temperature
58 read-only, floating point
59 Temperature read by the chip at high resolution (~13 bits). Units are
60 selected from the invoking command line. See owfs(1) or owhttpd(1) for
61 choices. Default is Celsius.
62 Conversion is continuous.
63
64 vbias
65 read-write, floating point
66 Fixed offset applied to each vis measurement. Used for the volthours
67 value. Units are in Volts.
68 Range -2.0mV to 2.0mV
69
70 vis
71 read-only, floating point
72 Current sensor reading (unknown external resistor). Measures the volt‐
73 age gradient between the Vis pins. Units are in Volts
74 The vis readings are integrated over time to provide the volthours
75 property.
76 The current reading is derived from vis assuming the internal 25 mOhm
77 resistor is employed. There is no way to know this through software.
78
79 vis_avg
80 read-only, floating point
81 Average current sensor reading (unknown external resistor). Measures
82 the voltage gradient between the Vis pins. Units are in Volts
83
84 vis_offset
85 read-write, floating point
86 Offset to vis for current sensor reading (unknown external resistor).
87 Units are in Volts
88
89 volt
90 read-only, floating point
91 Voltage read at the voltage sensor;. This is separate from the vis
92 voltage that is used for current measurement. Units are Volts
93 Range is between 0 and 4.75V
94
95 volthours
96 read-write, floating point
97 Integral of vis - vbias over time. Units are in volthours
98
100 typeX/
101 directory
102 Thermocouple circuit using the DS2781 to read the Seebeck voltage and
103 the reference temperature. Since the type interpretation of the values
104 read depends on the type of thermocouple, the correct directory must be
105 chosen. Supported thermocouple types include types B, E, J, K, N, R, S
106 and T.
107
108 typeX/range_low typeX/ranges_high
109 read-only, flaoting point
110 The lower and upper temperature supported by this thermocouple (at
111 least by the conversion routines). In the globally chosen temperature
112 units.
113
114 typeX/temperature
115 read-only, floating point
116 Thermocouple temperature. Requires a voltage and temperature conver‐
117 sion. Returned in globally chosen temperature units.
118 Note: there are two types of temperature measurements possible. The
119 temperature value in the main device directory is the reference temper‐
120 ature read at the chip. The typeX/temperature value is at the thermo‐
121 couple junction, probably remote from the chip.
122
124 aef chgtf learnf pmod porf sef uven uvf
125 varies, yes-no
126 Bit flags corresponding to various battery management functions of the
127 chip. See the DATASHEET for details of the identically named entries.
128 In general, writing "0" corresponds to a 0 bit value, and non-zero cor‐
129 responds to a 1 bit value.
130
132 address
133 r_address
134 read-only, ascii
135 The entire 64-bit unique ID. Given as upper case hexidecimal digits
136 (0-9A-F).
137 address starts with the family code
138 r address is the address in reverse order, which is often used in other
139 applications and labeling.
140
141 crc8
142 read-only, ascii
143 The 8-bit error correction portion. Uses cyclic redundancy check. Com‐
144 puted from the preceding 56 bits of the unique ID number. Given as
145 upper case hexadecimal digits (0-9A-F).
146
147 family
148 read-only, ascii
149 The 8-bit family code. Unique to each type of device. Given as upper
150 case hexadecimal digits (0-9A-F).
151
152 id
153 r_id
154 read-only, ascii
155 The 48-bit middle portion of the unique ID number. Does not include the
156 family code or CRC. Given as upper case hexadecimal digits (0-9A-F).
157 r id is the id in reverse order, which is often used in other applica‐
158 tions and labeling.
159
160 locator
161 r_locator
162 read-only, ascii
163 Uses an extension of the 1-wire design from iButtonLink company that
164 associated 1-wire physical connections with a unique 1-wire code. If
165 the connection is behind a Link Locator the locator will show a unique
166 8-byte number (16 character hexadecimal) starting with family code FE.
167 If no Link Locator is between the device and the master, the locator
168 field will be all FF.
169 r locator is the locator in reverse order.
170
171 present (DEPRECATED)
172 read-only, yes-no
173 Is the device currently present on the 1-wire bus?
174
175 type
176 read-only, ascii
177 Part name assigned by Dallas Semi. E.g. DS2401 Alternative packaging
178 (iButton vs chip) will not be distiguished.
179
181 None.
182
184 1-Wire
185 1-wire is a wiring protocol and series of devices designed and manufac‐
186 tured by Dallas Semiconductor, Inc. The bus is a low-power low-speed
187 low-connector scheme where the data line can also provide power.
188
189 Each device is uniquely and unalterably numbered during manufacture.
190 There are a wide variety of devices, including memory, sensors (humid‐
191 ity, temperature, voltage, contact, current), switches, timers and data
192 loggers. More complex devices (like thermocouple sensors) can be built
193 with these basic devices. There are also 1-wire devices that have
194 encryption included.
195
196 The 1-wire scheme uses a single bus master and multiple slaves on the
197 same wire. The bus master initiates all communication. The slaves can
198 be individually discovered and addressed using their unique ID.
199
200 Bus masters come in a variety of configurations including serial, par‐
201 allel, i2c, network or USB adapters.
202
203 OWFS design
204 OWFS is a suite of programs that designed to make the 1-wire bus and
205 its devices easily accessible. The underlying principle is to create a
206 virtual filesystem, with the unique ID being the directory, and the
207 individual properties of the device are represented as simple files
208 that can be read and written.
209
210 Details of the individual slave or master design are hidden behind a
211 consistent interface. The goal is to provide an easy set of tools for a
212 software designer to create monitoring or control applications. There
213 are some performance enhancements in the implementation, including data
214 caching, parallel access to bus masters, and aggregation of device com‐
215 munication. Still the fundamental goal has been ease of use, flexibil‐
216 ity and correctness rather than speed.
217
218 DS2781
219 The DS2781 (3) is a battery charging controller. It has elaborate algo‐
220 rithms for estimating battery capacity.
221
222 A number of interesting devices can be built with the DS2781 including
223 thermocouples. Support for thermocouples in built into the software,
224 using the embedded thermister as the cold junction temperature.
225
227 All 1-wire devices are factory assigned a unique 64-bit address. This
228 address is of the form:
229
230 Family Code
231 8 bits
232
233 Address
234 48 bits
235
236 CRC 8 bits
237
238 Addressing under OWFS is in hexadecimal, of form:
239
240 01.123456789ABC
241
242 where 01 is an example 8-bit family code, and 12345678ABC is an example
243 48 bit address.
244
245 The dot is optional, and the CRC code can included. If included, it
246 must be correct.
247
249 http://pdfserv.maxim-ic.com/en/ds/DS2781.pdf
250
252 Programs
253 owfs (1) owhttpd (1) owftpd (1) owserver (1) owdir (1) owread (1)
254 owwrite (1) owpresent (1) owtap (1)
255
256 Configuration and testing
257 owfs (5) owtap (1) owmon (1)
258
259 Language bindings
260 owtcl (3) owperl (3) owcapi (3)
261
262 Clocks
263 DS1427 (3) DS1904 (3) DS1994 (3) DS2404 (3) DS2404S (3) DS2415 (3)
264 DS2417 (3)
265
266 ID
267 DS2401 (3) DS2411 (3) DS1990A (3)
268
269 Memory
270 DS1982 (3) DS1985 (3) DS1986 (3) DS1991 (3) DS1992 (3) DS1993 (3)
271 DS1995 (3) DS1996 (3) DS2430A (3) DS2431 (3) DS2433 (3) DS2502 (3)
272 DS2506 (3) DS28E04 (3) DS28EC20 (3)
273
274 Switches
275 DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3)
276
277 Temperature
278 DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3)
279 DS1921 (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3)
280 EDS0066 (3) EDS0067 (3) EDS0068 (3) EDS0071 (3) EDS0072 (3) MAX31826
281 [1m(3)
282
283 Humidity
284 DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)
285
286 Voltage
287 DS2450 (3)
288
289 Resistance
290 DS2890 (3)
291
292 Multifunction (current, voltage, temperature)
293 DS2436 (3) DS2437 (3) DS2438 (3) DS2751 (3) DS2755 (3) DS2756 (3)
294 DS2760 (3) DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)
295
296 Counter
297 DS2423 (3)
298
299 LCD Screen
300 LCD (3) DS2408 (3)
301
302 Crypto
303 DS1977 (3)
304
305 Pressure
306 DS2406 (3) TAI8570 (3) EDS0066 (3) EDS0068 (3)
307
308 Moisture
309 EEEF (3) DS2438 (3)
310
312 http://www.owfs.org
313
315 Paul Alfille (paul.alfille@gmail.com)
316
317
318
319OWFS Manpage 2003 DS2760(3)