1DS2751(3) One-Wire File System DS2751(3)
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6 DS2751 - Multichemistry Battery Fuel Gauge
7
9 Temperature Voltage, Current, Memory, and Switch.
10 51 [.]XXXXXXXXXXXX[XX][/[ amphours | current | currentbias |
11 lock.[0-1|ALL] | memory | pages/page.[0-1|ALL] | PIO | sensed | temper‐
12 ature | typeX/range_low | typeX/range_high | typeX/temperature | vbias
13 | vis | volt | volthours |
14 defaultpmod | pmod | por | uven |
15 address | crc8 | id | locator | r_address | r_id | r_locator | type ]]
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17 Thermocouple
18 51 [.]XXXXXXXXXXXX[XX][/[ temperature | typeX/range_low |
19 typeX/range_high | typeX/temperature
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22 51
23
25 amphours
26 read-write, floating point
27 Accumulated amperage read by current sensor. Units are in Amp-hr
28 (Assumes internal 25mOhm resistor). Derived from volthours / Rinternal.
29 Formally amphours is the integral of current - currentbias over time.
30
31 current
32 read-only, floating point
33 Current reading. Units are in Amp (Assumes internal 25 mOhm resistor).
34 Derived from vis / Rinternal.
35
36 currentbias
37 read-write, floating point
38 Fixed offset applied to each current measurement. Used in the amphours
39 value. Assumes internal 25mOhm resistor. Units are Amp and range from
40 -.08A to .08A.
41 Derived from vbias / Rinternal.
42
43 lock.[0-1|ALL]
44 read-write, yes-no
45 Lock either of the two eprom pages to prevent further writes. Appar‐
46 ently setting lock is permanent.
47
48 memory
49 read-write, binary
50 Access to the full 256 byte memory range. Much of this space is
51 reserved or special use. User space is the page area.
52 See the DATASHEET for a full memory map.
53
54 pages/pages.[0-1|ALL]
55 read-write, binary Two 16 byte areas of memory for user application.
56 The lock property can prevent further alteration.
57 NOTE that the page property is different from the common OWFS implemen‐
58 tation in that all of memory is not accessible.
59
60 PIO
61 write-only, yes-no
62 Controls the PIO pin allowing external switching.
63 Writing "1" turns the PIO pin on (conducting). Writing "0" makes the
64 pin non-conducting. The logical state of the voltage can be read with
65 the sensed property. This will reflect the current voltage at the pin,
66 not the value sent to PIO
67 Note also that PIO will also be altered by the power-status of the
68 DS2670 See the datasheet for details.
69
70 sensed
71 read-only, yes-no
72 The logical voltage at the PIO pin. Useful only if the PIO property is
73 set to "0" (non-conducting).
74 Value will be 0 or 1 depending on the voltage threshold.
75
76 temperature
77 read-only, floating point
78 Temperature read by the chip at high resolution (~13 bits). Units are
79 selected from the invoking command line. See owfs(1) or owhttpd(1) for
80 choices. Default is Celsius.
81 Conversion is continuous.
82
83 vbias
84 read-write, floating point
85 Fixed offset applied to each vis measurement. Used for the volthours
86 value. Units are in Volts.
87 Range -2.0mV to 2.0mV
88
89 vis
90 read-only, floating point
91 Current sensor reading (unknown external resistor). Measures the volt‐
92 age gradient between the Vis pins. Units are in Volts
93 The vis readings are integrated over time to provide the volthours
94 property.
95 The current reading is derived from vis assuming the internal 25 mOhm
96 resistor is employed. There is no way to know this through software.
97
98 volt
99 read-only, floating point
100 Voltage read at the voltage sensor;. This is separate from the vis
101 voltage that is used for current measurement. Units are Volts
102 Range is between 0 and 4.75V
103
104 volthours
105 read-write, floating point
106 Integral of vis - vbias over time. Units are in volthours
107
109 typeX/
110 directory
111 Thermocouple circuit using the DS2760 to read the Seebeck voltage and
112 the reference temperature. Since the type interpretation of the values
113 read depends on the type of thermocouple, the correct directory must be
114 chosen. Supported thermocouple types include types B, E, J, K, N, R, S
115 and T.
116
117 typeX/range_low typeX/ranges_high
118 read-only, flaoting point
119 The lower and upper temperature supported by this thermocouple (at
120 least by the conversion routines). In the globally chosen temperature
121 units.
122
123 typeX/temperature
124 read-only, floating point
125 Thermocouple temperature. Requires a voltage and temperature conver‐
126 sion. Returned in globally chosen temperature units.
127 Note: there are two types of temperature measurements possible. The
128 temperature value in the main device directory is the reference temper‐
129 ature read at the chip. The typeX/temperature value is at the thermo‐
130 couple junction, probably remote from the chip.
131
133 pmod por uven
134 varies, yes-no
135 Bit flags corresponding to various battery management functions of the
136 chip. See the DATASHEET for details of the identically named entries.
137 In general, writing "0" corresponds to a 0 bit value, and non-zero cor‐
138 responds to a 1 bit value.
139
140 defaultpmod
141 read-write, yes-no
142 Default power-on state for the corresponding properties.
143
145 address
146 r_address
147 read-only, ascii
148 The entire 64-bit unique ID. Given as upper case hexidecimal digits
149 (0-9A-F).
150 address starts with the family code
151 r address is the address in reverse order, which is often used in other
152 applications and labeling.
153
154 crc8
155 read-only, ascii
156 The 8-bit error correction portion. Uses cyclic redundancy check. Com‐
157 puted from the preceding 56 bits of the unique ID number. Given as
158 upper case hexadecimal digits (0-9A-F).
159
160 family
161 read-only, ascii
162 The 8-bit family code. Unique to each type of device. Given as upper
163 case hexadecimal digits (0-9A-F).
164
165 id
166 r_id
167 read-only, ascii
168 The 48-bit middle portion of the unique ID number. Does not include the
169 family code or CRC. Given as upper case hexadecimal digits (0-9A-F).
170 r id is the id in reverse order, which is often used in other applica‐
171 tions and labeling.
172
173 locator
174 r_locator
175 read-only, ascii
176 Uses an extension of the 1-wire design from iButtonLink company that
177 associated 1-wire physical connections with a unique 1-wire code. If
178 the connection is behind a Link Locator the locator will show a unique
179 8-byte number (16 character hexadecimal) starting with family code FE.
180 If no Link Locator is between the device and the master, the locator
181 field will be all FF.
182 r locator is the locator in reverse order.
183
184 present (DEPRECATED)
185 read-only, yes-no
186 Is the device currently present on the 1-wire bus?
187
188 type
189 read-only, ascii
190 Part name assigned by Dallas Semi. E.g. DS2401 Alternative packaging
191 (iButton vs chip) will not be distiguished.
192
194 None.
195
197 1-Wire
198 1-wire is a wiring protocol and series of devices designed and manufac‐
199 tured by Dallas Semiconductor, Inc. The bus is a low-power low-speed
200 low-connector scheme where the data line can also provide power.
201
202 Each device is uniquely and unalterably numbered during manufacture.
203 There are a wide variety of devices, including memory, sensors (humid‐
204 ity, temperature, voltage, contact, current), switches, timers and data
205 loggers. More complex devices (like thermocouple sensors) can be built
206 with these basic devices. There are also 1-wire devices that have
207 encryption included.
208
209 The 1-wire scheme uses a single bus master and multiple slaves on the
210 same wire. The bus master initiates all communication. The slaves can
211 be individually discovered and addressed using their unique ID.
212
213 Bus masters come in a variety of configurations including serial, par‐
214 allel, i2c, network or USB adapters.
215
216 OWFS design
217 OWFS is a suite of programs that designed to make the 1-wire bus and
218 its devices easily accessible. The underlying principle is to create a
219 virtual filesystem, with the unique ID being the directory, and the
220 individual properties of the device are represented as simple files
221 that can be read and written.
222
223 Details of the individual slave or master design are hidden behind a
224 consistent interface. The goal is to provide an easy set of tools for a
225 software designer to create monitoring or control applications. There
226 are some performance enhancements in the implementation, including data
227 caching, parallel access to bus masters, and aggregation of device com‐
228 munication. Still the fundamental goal has been ease of use, flexibil‐
229 ity and correctness rather than speed.
230
231 DS2751
232 The DS2751 (3) is battery charging controllers similar to the DS2760
233 [1m(3)
234
235 A number of interesting devices can be built with the DS2751 (3)
236 including thermocouples. Support for thermocouples in built into the
237 software, using the embedded thermister as the cold junction tempera‐
238 ture.
239
241 All 1-wire devices are factory assigned a unique 64-bit address. This
242 address is of the form:
243
244 Family Code
245 8 bits
246
247 Address
248 48 bits
249
250 CRC 8 bits
251
252 Addressing under OWFS is in hexadecimal, of form:
253
254 01.123456789ABC
255
256 where 01 is an example 8-bit family code, and 12345678ABC is an example
257 48 bit address.
258
259 The dot is optional, and the CRC code can included. If included, it
260 must be correct.
261
263 http://pdfserv.maxim-ic.com/en/ds/DS2751.pdf
264
266 Programs
267 owfs (1) owhttpd (1) owftpd (1) owserver (1) owdir (1) owread (1)
268 owwrite (1) owpresent (1) owtap (1)
269
270 Configuration and testing
271 owfs (5) owtap (1) owmon (1)
272
273 Language bindings
274 owtcl (3) owperl (3) owcapi (3)
275
276 Clocks
277 DS1427 (3) DS1904 (3) DS1994 (3) DS2404 (3) DS2404S (3) DS2415 (3)
278 DS2417 (3)
279
280 ID
281 DS2401 (3) DS2411 (3) DS1990A (3)
282
283 Memory
284 DS1982 (3) DS1985 (3) DS1986 (3) DS1991 (3) DS1992 (3) DS1993 (3)
285 DS1995 (3) DS1996 (3) DS2430A (3) DS2431 (3) DS2433 (3) DS2502 (3)
286 DS2506 (3) DS28E04 (3) DS28EC20 (3)
287
288 Switches
289 DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3)
290
291 Temperature
292 DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3)
293 DS1921 (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3)
294 EDS0066 (3) EDS0067 (3) EDS0068 (3) EDS0071 (3) EDS0072 (3) MAX31826
295 [1m(3)
296
297 Humidity
298 DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)
299
300 Voltage
301 DS2450 (3)
302
303 Resistance
304 DS2890 (3)
305
306 Multifunction (current, voltage, temperature)
307 DS2436 (3) DS2437 (3) DS2438 (3) DS2751 (3) DS2755 (3) DS2756 (3)
308 DS2760 (3) DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)
309
310 Counter
311 DS2423 (3)
312
313 LCD Screen
314 LCD (3) DS2408 (3)
315
316 Crypto
317 DS1977 (3)
318
319 Pressure
320 DS2406 (3) TAI8570 (3) EDS0066 (3) EDS0068 (3)
321
322 Moisture
323 EEEF (3) DS2438 (3)
324
326 http://www.owfs.org
327
329 Paul Alfille (paul.alfille@gmail.com)
330
331
332
333OWFS Manpage 2003 DS2751(3)