1DS2720(3)                    One-Wire File System                    DS2720(3)
2
3
4

NAME

6       DS2720 - Efficient Addressable Single-cell Rechargeable Lithium Protec‐
7       tion IC
8

SYNOPSIS

10       Memory and warnings.
11
12       31     [.]XXXXXXXXXXXX[XX][/[     lock.[0-1|ALL]     |     memory     |
13       pages/page.[0-1|ALL] |
14       cc | ce | dc | de | doc | ot | ov | psf | uv |
15       address | crc8 | id | locator | r_address | r_id | r_locator | type ]]
16

FAMILY CODE

18       31
19

SPECIAL PROPERTIES

21   lock.[0-1|ALL]
22       read-write, yes-no
23       Lock  either  of  the two eprom pages to prevent further writes. Appar‐
24       ently setting lock is permanent.
25
26   memory
27       read-write, binary
28       Access to the full 256  byte  memory  range.  Much  of  this  space  is
29       reserved or special use. User space is the page area.
30       See the DATASHEET for a full memory map.
31
32   pages/pages.[0-1|ALL]
33       read-write, binary Two 8 byte areas of memory for user application. The
34       lock property can prevent further alteration.
35       NOTE that the page property is different from the common OWFS implemen‐
36       tation in that all of memory is not accessible.
37

OBSCURE PROPERTIES

39   cc ce dc de doc ot ov uv
40       varies, yes-no
41       Bit  flags corresponding to various battery management functions of the
42       chip. See the DATASHEET for details of the identically named entries.
43       In general, writing "0" corresponds to a 0 bit value, and non-zero cor‐
44       responds to a 1 bit value.
45

STANDARD PROPERTIES

47   address
48   r_address
49       read-only, ascii
50       The  entire  64-bit  unique  ID. Given as upper case hexidecimal digits
51       (0-9A-F).
52       address starts with the family code
53       r address is the address in reverse order, which is often used in other
54       applications and labeling.
55
56   crc8
57       read-only, ascii
58       The  8-bit error correction portion. Uses cyclic redundancy check. Com‐
59       puted from the preceding 56 bits of the  unique  ID  number.  Given  as
60       upper case hexadecimal digits (0-9A-F).
61
62   family
63       read-only, ascii
64       The  8-bit  family  code. Unique to each type of device. Given as upper
65       case hexadecimal digits (0-9A-F).
66
67   id
68   r_id
69       read-only, ascii
70       The 48-bit middle portion of the unique ID number. Does not include the
71       family code or CRC. Given as upper case hexadecimal digits (0-9A-F).
72       r  id is the id in reverse order, which is often used in other applica‐
73       tions and labeling.
74
75   locator
76   r_locator
77       read-only, ascii
78       Uses an extension of the 1-wire design from  iButtonLink  company  that
79       associated  1-wire  physical  connections with a unique 1-wire code. If
80       the connection is behind a Link Locator the locator will show a  unique
81       8-byte number (16 character hexadecimal) starting with family code FE.
82       If  no  Link  Locator is between the device and the master, the locator
83       field will be all FF.
84       r locator is the locator in reverse order.
85
86   present (DEPRECATED)
87       read-only, yes-no
88       Is the device currently present on the 1-wire bus?
89
90   type
91       read-only, ascii
92       Part name assigned by Dallas Semi. E.g.  DS2401  Alternative  packaging
93       (iButton vs chip) will not be distiguished.
94

ALARMS

96       None.
97

DESCRIPTION

99   1-Wire
100       1-wire is a wiring protocol and series of devices designed and manufac‐
101       tured by Dallas Semiconductor, Inc. The bus is  a  low-power  low-speed
102       low-connector scheme where the data line can also provide power.
103
104       Each  device  is  uniquely and unalterably numbered during manufacture.
105       There are a wide variety of devices, including memory, sensors  (humid‐
106       ity, temperature, voltage, contact, current), switches, timers and data
107       loggers. More complex devices (like thermocouple sensors) can be  built
108       with  these  basic  devices.  There  are  also 1-wire devices that have
109       encryption included.
110
111       The 1-wire scheme uses a single bus master and multiple slaves  on  the
112       same  wire.  The bus master initiates all communication. The slaves can
113       be individually discovered and addressed using their unique ID.
114
115       Bus masters come in a variety of configurations including serial,  par‐
116       allel, i2c, network or USB adapters.
117
118   OWFS design
119       OWFS  is  a  suite of programs that designed to make the 1-wire bus and
120       its devices easily accessible. The underlying principle is to create  a
121       virtual  filesystem,  with  the  unique ID being the directory, and the
122       individual properties of the device are  represented  as  simple  files
123       that can be read and written.
124
125       Details  of  the  individual slave or master design are hidden behind a
126       consistent interface. The goal is to provide an easy set of tools for a
127       software  designer  to create monitoring or control applications. There
128       are some performance enhancements in the implementation, including data
129       caching, parallel access to bus masters, and aggregation of device com‐
130       munication. Still the fundamental goal has been ease of use,  flexibil‐
131       ity and correctness rather than speed.
132
133   DS2720
134       The  DS2720  (3)  is  a battery charging monitor. Besides it's intended
135       use, it may have use in monitoring for device failures.
136

ADDRESSING

138       All 1-wire devices are factory assigned a unique 64-bit  address.  This
139       address is of the form:
140
141       Family Code
142              8 bits
143
144       Address
145              48 bits
146
147       CRC    8 bits
148
149       Addressing under OWFS is in hexadecimal, of form:
150
151              01.123456789ABC
152
153       where 01 is an example 8-bit family code, and 12345678ABC is an example
154       48 bit address.
155
156       The dot is optional, and the CRC code can  included.  If  included,  it
157       must be correct.
158

DATASHEET

160       http://pdfserv.maxim-ic.com/en/ds/DS2720.pdf
161

SEE ALSO

163   Programs
164       owfs  (1)  owhttpd  (1)  owftpd  (1)  owserver (1) owdir (1) owread (1)
165       owwrite (1) owpresent (1) owtap (1)
166
167   Configuration and testing
168       owfs (5) owtap (1) owmon (1)
169
170   Language bindings
171       owtcl (3) owperl (3) owcapi (3)
172
173   Clocks
174       DS1427 (3) DS1904 (3) DS1994 (3) DS2404  (3)  DS2404S  (3)  DS2415  (3)
175       DS2417 (3)
176
177   ID
178       DS2401 (3) DS2411 (3) DS1990A (3)
179
180   Memory
181       DS1982  (3)  DS1985  (3)  DS1986  (3)  DS1991 (3) DS1992 (3) DS1993 (3)
182       DS1995 (3) DS1996 (3) DS2430A (3) DS2431  (3)  DS2433  (3)  DS2502  (3)
183       DS2506 (3) DS28E04 (3) DS28EC20 (3)
184
185   Switches
186       DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3)
187
188   Temperature
189       DS1822  (3)  DS1825  (3)  DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3)
190       DS1921 (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065  (3)
191       EDS0066  (3)  EDS0067  (3) EDS0068 (3) EDS0071 (3) EDS0072 (3) MAX31826
192       (3)
193
194   Humidity
195       DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)
196
197   Voltage
198       DS2450 (3)
199
200   Resistance
201       DS2890 (3)
202
203   Multifunction (current, voltage, temperature)
204       DS2436 (3) DS2437 (3) DS2438 (3)  DS2751  (3)  DS2755  (3)  DS2756  (3)
205       DS2760 (3) DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)
206
207   Counter
208       DS2423 (3)
209
210   LCD Screen
211       LCD (3) DS2408 (3)
212
213   Crypto
214       DS1977 (3)
215
216   Pressure
217       DS2406 (3) TAI8570 (3) EDS0066 (3) EDS0068 (3)
218
219   Moisture
220       EEEF (3) DS2438 (3)
221

AVAILABILITY

223       http://www.owfs.org
224

AUTHOR

226       Paul Alfille (paul.alfille@gmail.com)
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230OWFS Manpage                         2003                            DS2720(3)
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