1DS2755(3) One-Wire File System DS2755(3)
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6 DS2755, DS2756 - Multichemistry Battery Fuel Gauge
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9 Temperature Voltage, Current, Memory, and Switch.
10 35 [.]XXXXXXXXXXXX[XX][/[ alarm_set/[volthigh|voltlow|temphigh|templow]
11 | lock.[0-2|ALL] | memory | pages/page.[0-2|ALL] | PIO | sensed | tem‐
12 perature | vbias | vis | volt | volthours |
13 defaultpmod | pie0 | pie1 | rnaop | ios | uben | ovd | pmod | por |
14 uven |
15 address | crc8 | id | locator | r_address | r_id | r_locator | type ]]
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17 Thermocouple
18 35 [.]XXXXXXXXXXXX[XX][/[ temperature | typeX/range_low |
19 typeX/range_high | typeX/temperature
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22 35
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25 alarm_set/templow alarm_set/temphigh
26 read-write, integer
27 High and low alarm settings for temperature
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29 alarm_set/voltlow alarm_set/volthigh
30 read-write, floating point
31 High and low alarm settings for volts
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33 lock.[0-2|ALL]
34 read-write, yes-no
35 Lock any of the three eprom pages to prevent further writes. Apparently
36 setting lock is permanent.
37
38 memory
39 read-write, binary
40 Access to the full 256 byte memory range. Much of this space is
41 reserved or special use. User space is the page area.
42 See the DATASHEET for a full memory map.
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44 pages/pages.[0-2|ALL]
45 read-write, binary Three 32 byte areas of memory for user application.
46 The lock property can prevent further alteration.
47 NOTE that the page property is different from the common OWFS implemen‐
48 tation in that all of memory is not accessible.
49
50 PIO
51 write-only, yes-no
52 Controls the PIO pin allowing external switching.
53 Writing "1" turns the PIO pin on (conducting). Writing "0" makes the
54 pin non-conducting. The logical state of the voltage can be read with
55 the sensed property. This will reflect the current voltage at the pin,
56 not the value sent to PIO
57 Note also that PIO will also be altered by the power-status of the
58 DS2670 See the datasheet for details.
59
60 sensed
61 read-only, yes-no
62 The logical voltage at the PIO pin. Useful only if the PIO property is
63 set to "0" (non-conducting).
64 Value will be 0 or 1 depending on the voltage threshold.
65
66 temperature
67 read-only, floating point
68 Temperature read by the chip at high resolution (~13 bits). Units are
69 selected from the invoking command line. See owfs(1) or owhttpd(1) for
70 choices. Default is Celsius.
71 Conversion is continuous.
72
73 vbias
74 read-write, floating point
75 Fixed offset applied to each vis measurement. Used for the volthours
76 value. Units are in Volts.
77 Range -2.0mV to 2.0mV
78
79 vis
80 read-only, floating point
81 Current sensor reading (unknown external resistor). Measures the volt‐
82 age gradient between the Vis pins. Units are in Volts
83 The vis readings are integrated over time to provide the volthours
84 property.
85 The current reading is derived from vis assuming the internal 25 mOhm
86 resistor is employed. There is no way to know this through software.
87
88 volt
89 read-only, floating point
90 Voltage read at the voltage sensor;. This is separate from the vis
91 voltage that is used for current measurement. Units are Volts
92 Range is between 0 and 4.75V
93
94 volthours
95 read-write, floating point
96 Integral of vis - vbias over time. Units are in volthours
97
99 typeX/
100 directory
101 Thermocouple circuit using the DS2755 to read the Seebeck voltage and
102 the reference temperature. Since the type interpretation of the values
103 read depends on the type of thermocouple, the correct directory must be
104 chosen. Supported thermocouple types include types B, E, J, K, N, R, S
105 and T.
106
107 typeX/range_low typeX/ranges_high
108 read-only, flaoting point
109 The lower and upper temperature supported by this thermocouple (at
110 least by the conversion routines). In the globally chosen temperature
111 units.
112
113 typeX/temperature
114 read-only, floating point
115 Thermocouple temperature. Requires a voltage and temperature conver‐
116 sion. Returned in globally chosen temperature units.
117 Note: there are two types of temperature measurements possible. The
118 temperature value in the main device directory is the reference temper‐
119 ature read at the chip. The typeX/temperature value is at the thermo‐
120 couple junction, probably remote from the chip.
121
123 pmod por uven pie0 pie1 ios uben ovd rnaop
124 varies, yes-no
125 Bit flags corresponding to various battery management functions of the
126 chip. See the DATASHEET for details of the identically named entries.
127 In general, writing "0" corresponds to a 0 bit value, and non-zero cor‐
128 responds to a 1 bit value.
129
130 defaultpmod
131 read-write, yes-no
132 Default power-on state for the corresponding properties.
133
135 address
136 r_address
137 read-only, ascii
138 The entire 64-bit unique ID. Given as upper case hexidecimal digits
139 (0-9A-F).
140 address starts with the family code
141 r address is the address in reverse order, which is often used in other
142 applications and labeling.
143
144 crc8
145 read-only, ascii
146 The 8-bit error correction portion. Uses cyclic redundancy check. Com‐
147 puted from the preceding 56 bits of the unique ID number. Given as
148 upper case hexadecimal digits (0-9A-F).
149
150 family
151 read-only, ascii
152 The 8-bit family code. Unique to each type of device. Given as upper
153 case hexadecimal digits (0-9A-F).
154
155 id
156 r_id
157 read-only, ascii
158 The 48-bit middle portion of the unique ID number. Does not include the
159 family code or CRC. Given as upper case hexadecimal digits (0-9A-F).
160 r id is the id in reverse order, which is often used in other applica‐
161 tions and labeling.
162
163 locator
164 r_locator
165 read-only, ascii
166 Uses an extension of the 1-wire design from iButtonLink company that
167 associated 1-wire physical connections with a unique 1-wire code. If
168 the connection is behind a Link Locator the locator will show a unique
169 8-byte number (16 character hexadecimal) starting with family code FE.
170 If no Link Locator is between the device and the master, the locator
171 field will be all FF.
172 r locator is the locator in reverse order.
173
174 present (DEPRECATED)
175 read-only, yes-no
176 Is the device currently present on the 1-wire bus?
177
178 type
179 read-only, ascii
180 Part name assigned by Dallas Semi. E.g. DS2401 Alternative packaging
181 (iButton vs chip) will not be distiguished.
182
184 Temperature and voltage.
185
187 1-Wire
188 1-wire is a wiring protocol and series of devices designed and manufac‐
189 tured by Dallas Semiconductor, Inc. The bus is a low-power low-speed
190 low-connector scheme where the data line can also provide power.
191
192 Each device is uniquely and unalterably numbered during manufacture.
193 There are a wide variety of devices, including memory, sensors (humid‐
194 ity, temperature, voltage, contact, current), switches, timers and data
195 loggers. More complex devices (like thermocouple sensors) can be built
196 with these basic devices. There are also 1-wire devices that have
197 encryption included.
198
199 The 1-wire scheme uses a single bus master and multiple slaves on the
200 same wire. The bus master initiates all communication. The slaves can
201 be individually discovered and addressed using their unique ID.
202
203 Bus masters come in a variety of configurations including serial, par‐
204 allel, i2c, network or USB adapters.
205
206 OWFS design
207 OWFS is a suite of programs that designed to make the 1-wire bus and
208 its devices easily accessible. The underlying principle is to create a
209 virtual filesystem, with the unique ID being the directory, and the
210 individual properties of the device are represented as simple files
211 that can be read and written.
212
213 Details of the individual slave or master design are hidden behind a
214 consistent interface. The goal is to provide an easy set of tools for a
215 software designer to create monitoring or control applications. There
216 are some performance enhancements in the implementation, including data
217 caching, parallel access to bus masters, and aggregation of device com‐
218 munication. Still the fundamental goal has been ease of use, flexibil‐
219 ity and correctness rather than speed.
220
221 DS2755 DS2756
222 The DS2755 (3) and DS2756 (3) are battery charging controllers similar
223 to the DS2751 (3) except no internal resistor option and a larger EEP‐
224 ROM memory.
225
226 The DS2756 (3) adds suspend modes ( pie0 pie1 ) to the DS2755 (3)
227
228 A number of interesting devices can be built with the DS2755 (3) and
229 DS2756 (3) including thermocouples. Support for thermocouples in built
230 into the software, using the embedded thermister as the cold junction
231 temperature.
232
234 All 1-wire devices are factory assigned a unique 64-bit address. This
235 address is of the form:
236
237 Family Code
238 8 bits
239
240 Address
241 48 bits
242
243 CRC 8 bits
244
245 Addressing under OWFS is in hexadecimal, of form:
246
247 01.123456789ABC
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249 where 01 is an example 8-bit family code, and 12345678ABC is an example
250 48 bit address.
251
252 The dot is optional, and the CRC code can included. If included, it
253 must be correct.
254
256 http://pdfserv.maxim-ic.com/en/ds/DS2755.pdf
257 http://pdfserv.maxim-ic.com/en/ds/DS2756.pdf
258
260 Programs
261 owfs (1) owhttpd (1) owftpd (1) owserver (1) owdir (1) owread (1)
262 owwrite (1) owpresent (1) owtap (1)
263
264 Configuration and testing
265 owfs (5) owtap (1) owmon (1)
266
267 Language bindings
268 owtcl (3) owperl (3) owcapi (3)
269
270 Clocks
271 DS1427 (3) DS1904 (3) DS1994 (3) DS2404 (3) DS2404S (3) DS2415 (3)
272 DS2417 (3)
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274 ID
275 DS2401 (3) DS2411 (3) DS1990A (3)
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277 Memory
278 DS1982 (3) DS1985 (3) DS1986 (3) DS1991 (3) DS1992 (3) DS1993 (3)
279 DS1995 (3) DS1996 (3) DS2430A (3) DS2431 (3) DS2433 (3) DS2502 (3)
280 DS2506 (3) DS28E04 (3) DS28EC20 (3)
281
282 Switches
283 DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3)
284
285 Temperature
286 DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3)
287 DS1921 (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3)
288 EDS0066 (3) EDS0067 (3) EDS0068 (3) EDS0071 (3) EDS0072 (3) MAX31826
289 [1m(3)
290
291 Humidity
292 DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)
293
294 Voltage
295 DS2450 (3)
296
297 Resistance
298 DS2890 (3)
299
300 Multifunction (current, voltage, temperature)
301 DS2436 (3) DS2437 (3) DS2438 (3) DS2751 (3) DS2755 (3) DS2756 (3)
302 DS2760 (3) DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)
303
304 Counter
305 DS2423 (3)
306
307 LCD Screen
308 LCD (3) DS2408 (3)
309
310 Crypto
311 DS1977 (3)
312
313 Pressure
314 DS2406 (3) TAI8570 (3) EDS0066 (3) EDS0068 (3)
315
316 Moisture
317 EEEF (3) DS2438 (3)
318
320 http://www.owfs.org
321
323 Paul Alfille (paul.alfille@gmail.com)
324
325
326
327OWFS Manpage 2003 DS2755(3)