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Technical Reference Documents Application
Note 27: "The Dallas Semiconductor iButton products are a
family of devices that all communicate over a single wire following a
specific command sequence referred to as the 1-Wire® Protocol. A key
feature of each device is a unique 8-byte ROM code written into each part
at the time of manufacture." Other information contained in this
application note includes the background and description of 1-Wire
devices, diagrams of applications utilizing the devices, sample code, and
details on CRC.
Application
Note 31: BCD clocks store time as a binary count of seconds that
have elapsed since a given time, typically midnight, 01-0-1970. This
application note presents code in pseudocode and Pascal for converting the
BCD clock's count of elapsed seconds into a date/time readout.
Application
Note 58: This note advises designers how to maximize accuracy and
performance when using Dallas real time clock chips with an external
crystal. Topics include choosing a crystal that matches the specified load
capacitance; compensating for crystals with a load capacitance other than
that specified by the RTC, using layouts to diminish EMI and noisy clock
inputs; and a brief discussion on the effects of temperature on clock
accuracy.
Application
Note 60: This note describes techniques to ensure accurate time
displays using an environmentally stable DS1994, a simple algorithm, and
access to an accurate timekeeping standard. Once the algorithm
coefficients specific to a DS1994 are determined, they can be stored in
the DS1994's memory. Four different programs developed for the DS1994
characterize coefficients automatically and adjust the time displays.
Using these techniques, calibration tests of DS1994s show <30
seconds/year error.
Application
Note 74: The Dallas 1-Wire interface reduces the data bus to the
absolute minimum, i.e., a single data line and a ground reference. This
application note contains information about the 1-Wire interface, the
fundamentals of 1-Wire devices (including TTL and RS232 interfaces), reset
and presence detect, read/write one bit, circuits for 5V interfaces, an
example of 8051 Assembly language (11.0592MHz and 1.8432MHz), C language
for Uart 8250 systems, C language pulsewidth for systems using 8253 and
8250, Pascal language for Uart 8250 systems, Pascal language pulsewidth
for systems using 8253 and 8250, and more. Diagrams detail various
functionality of the device.
Application
Note 96: Software vendors can easily and effectively protect
intellectual property by tying software execution to essential code
securely stored in portable iButton RAM. While software can be
copied, the iButton memory cannot. This note describes how
iButton technology saves money in rental, demo promotion and
multiple-vendor software distribution schemes.
Application
Note 97: Originally a plan for licensed software protection, this
note outlines how general principles of iButton security apply to
any computer access control application. A major benefit to the user is
the ability to dynamically generate passwords from an algorithm that
incorporates the iButton's unique, factory-lasered registration
number. The iButton itself incorporates hardware and software
levels of protection that counter decipherment attacks.
Application
Note 98: iButtons bridge bi-level security between two kinds
of distributed information systems: 1) company LAN networks, where
information managers must control access to confidential files and
program; and 2) retail software, where vendors must control copy
distribution. In either system, an iButton's unique registration
number links an associated user with a specific set of access permissions
in one centrally managed file. To access authorized files and/or programs,
the user must have the iButton (bring something) and a password
(know something) for two-level access security.
Application
Note 99: UniqueWare devices feature EPROM (one-time programmable
memory) that the user can configure to electronically label items and, if
desired, store relevant text. Besides a description of UniqueWare memory
structure, this note provides a text instruction guide to accompany the
program, downloaded from Dallas' Web site, that walks the user through
setting up and configuring this memory.
Application
Note 104: "The Minimalist Temperature Control Demo is a closed loop
1-Wire MicroLAN control system. It consists of a ready-to-use printed
circuit board, a cable with two RJ-11 connectors, and a disk with
software. In addition to this, the demo requires the DS9097 COM Port
Adapter." This application note contains information about the
configuration of the DS1820 Minimalist Temperature Kit, software
operation, a description of the graphical user interface temperature
control tab, a demo board circuit diagram, and more.
Application
Note 108: There are three rules to successfully network any number
of 1-Wire devices along buses up to 300 feet: 1) control the driver's slew
rate; 2) select a cable with optimal capacitance, inductance and
resistance properties; and 3) maintain an active pull-up across the bus to
control induction-generated voltage overshoots. This note provides
practical ways to either directly implement the rules or sidestep
potential problems.
Application
Note 114: The Extended File Structure described in the "Book of
DS19xx iButton Standards" enables iButton data files to be
randomly accessed, just like a diskette. Significant file properties
include page lengths and boundaries and the characterization of a
Universal Data Packet. This note extends such specifications to cover
"bitmap files for large capacity iButtons, multiple
sub-directories, extended file attributes, passwords, date-stamps, owner
identification, and other useful constructs."
Application
Note 117: The DS2490 is a communications bridge chip between a
1-Wire bus and a USB bus. This note tabulates the DS2490 descriptor
settings that inform the host processor of its capabilities and
characteristics, using USB core specifications for a Vendor-Specific
Device.
Application
Note 119: The DS1WM 1-Wire Master is a control block that generates
1-Wire timing and control signals. To incorporate the DS1WM into an ASIC
design, this note provides a wiring table, library requirement, and code
samples using Verilog to create a 1-Wire Master instance with a Synopsys
run script.
Application
Note 120: The DS1WM 1-Wire Master (1WM) is a control block that
generates 1-Wire timing and control signals. This application note
presents a specific 1WM application. In the sample configuration circuit,
the 1WM is embedded in an ASIC between a host CPU and four DS18B20 thermal
sensors. In the sample program (written in C with detailed comments), the
host requests, receives and stores temperatures through the 1WM.
Application
Note 122: Dallas' 1-Wire battery management products are designed
with the strategy to minimize electronics in the battery pack while
utilizing host-system resources whenever possible, to minimize battery
pack cost. The hardware design of a Dallas-based battery pack is quite
simple, with very few external components required.
Application
Note 126: A host CPU can easily generate 1-Wire timing signals
itself if a true bus master is not present. This is an example, written in
C, of how to perform the communication.
Standards, Assembly Guide, Tech Briefs & Magazine Articles Standards: Comprehensive reference of iButton and 1-Wire Chip
technologies. Contents include electrical and mechanical standards, bus
protocol definition, and TMEX software reference.
CSP
Assembly Guide: Addresses manufacturing, assembly, and reliability issues
associated with the use of solder-bumped die-size packages. Includes
recommendations for solder types, reflow temperature profiles, and
potential underfill/overcoat materials.
Tech Brief
1: This tech brief provides an overview of the 1-Wire bus
designed and developed by Dallas Semiconductor. It gives guidance on the
pitfalls and solutions involved in setting up a MicroLAN. It also
discusses active pull-ups, cabling, COM port adapters and opto-isolation.
Complete circuit schematics with values and guidelines are provided along
with a 1-Wire waveform template.
Article
1: Operational overview of the Dallas Semiconductor 1-Wire
interface. 1-Wire data and power transmission protocols are introduced as
well as the multi-device 1-Wire Network bus configuration.
Article
2: This application example demonstrates how multiple 1-Wire
chip devices can be configured in a low-cost, low-complexity, 1-Wire
Network and be used to implement sophisticated weather
instrumentation.
Article
3: This application example follow-up to the 1-Wire Weather
Station demonstrates the simplicity associated with adding 1-Wire devices
to an existing 1-Wire Network system. A 1-Wire rain gauge implemented with
1-Wire chip products is simply plugged into the 1-Wire bus port of the
1-Wire Weather Station to add rainfall measurement capability
Article
4: Operational overview of a humidity sensor designed for
retrofit into a 1-Wire weather station that is powered by and communicates
over a single twisted pair. |
Updated
2000/09/01 Problems or comments? |
Copyright © 2001 Dallas Semiconductor Corp. |