1DS2720(3) One-Wire File System DS2720(3)
2
6 DS2720 - Efficient Addressable Single-cell Rechargeable Lithium Protec‐
7 tion IC
8
10 Memory and warnings.
11 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
18 31
19
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 memory
27 read-write, binary
28 Access to the full 256 byte memory range. Much of this space is re‐
29 served or special use. User space is the page area.
30 See the DATASHEET for a full memory map.
31 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
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
47 address
48 r_address
49 read-only, ascii
50 The entire 64-bit unique ID. Given as upper case hexadecimal 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 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 up‐
60 per case hexadecimal digits (0-9A-F).
61 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 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 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 present (DEPRECATED)
87 read-only, yes-no
88 Is the device currently present on the 1-wire bus?
89 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
96 None.
97
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 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 en‐
109 cryption included.
110 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 Bus masters come in a variety of configurations including serial, par‐
116 allel, i2c, network or USB adapters.
117 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 in‐
122 dividual properties of the device are represented as simple files that
123 can be read and written.
124 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 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
138 All 1-wire devices are factory assigned a unique 64-bit address. This
139 address is of the form:
140 Family Code
142 8 bits
143 Address
145 48 bits
146 CRC 8 bits
148 Addressing under OWFS is in hexadecimal, of form:
150 01.123456789ABC
152 where 01 is an example 8-bit family code, and 12345678ABC is an example
154 48 bit address.
155 The dot is optional, and the CRC code can included. If included, it
157 must be correct.
158
160 http://pdfserv.maxim-ic.com/en/ds/DS2720.pdf
161
163 Programs
164 owfs (1) owhttpd (1) owftpd (1) owserver (1) owdir (1) owread (1)
165 owwrite (1) owpresent (1) owtap (1)
166 Configuration and testing
168 owfs (5) owtap (1) owmon (1)
169 Language bindings
171 owtcl (3) owperl (3) owcapi (3)
172 Clocks
174 DS1427 (3) DS1904 (3) DS1994 (3) DS2404 (3) DS2404S (3) DS2415 (3)
175 DS2417 (3)
176 ID
178 DS2401 (3) DS2411 (3) DS1990A (3)
179 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 Switches
186 DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3) In‐
187 fernoEmbedded (3)
188 Temperature
190 DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3)
191 DS1921 (3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3)
192 EDS0066 (3) EDS0067 (3) EDS0068 (3) EDS0071 (3) EDS0072 (3) MAX31826
193 [1m(3)
194 Humidity
196 DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)
197 Voltage
199 DS2450 (3)
200 Resistance
202 DS2890 (3)
203 Multifunction (current, voltage, temperature)
205 DS2436 (3) DS2437 (3) DS2438 (3) DS2751 (3) DS2755 (3) DS2756 (3)
206 DS2760 (3) DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)
207 Counter
209 DS2423 (3)
210 LCD Screen
212 LCD (3) DS2408 (3)
213 Crypto
215 DS1977 (3)
216 Pressure
218 DS2406 (3) TAI8570 (3) EDS0066 (3) EDS0068 (3)
219 Moisture
221 EEEF (3) DS2438 (3)
222
224 http://www.owfs.org
225
227 Paul Alfille (paul.alfille@gmail.com)
228OWFS Manpage 2003 DS2720(3)