NAME¶
DS28E04 - 1-Wire EEPROM chip (4096-bit) with seven address inputs
SYNOPSIS¶
4096-bit EEPROM, 2 port switch
1C [.]XXXXXXXXXXXX[XX][/[
latch.[0-1|ALL|BYTE] |
PIO.[0-1|ALL|BYTE] |
power |
sensed.[0-1|ALL|BYTE] |
polarity |
por |
set_alarm |
address |
crc8
|
id |
locator |
r_address |
r_id |
r_locator |
type ]]
FAMILY CODE¶
1C
SPECIAL PROPERTIES¶
latch.0 latch.1 latch.ALL latch.BYTE¶
read-write, binary
The 2 pins (PIO) latch a bit when their state changes, either externally, or
through a write to the pin.
Reading the
latch property indicates that the latch has been set.
Writing any data to ANY
latch will reset them all. (This is the hardware
design).
ALL is all
latch states, accessed simultaneously, comma separated.
BYTE references all channels simultaneously as a single byte. Channel 0
is bit 0.
PIO.0 PIO.1 PIO.ALL PIO.BYTE¶
read-write, yes-no
State of the open-drain output (
PIO ) pin. 0 = non-conducting = off, 1 =
conducting = on.
Writing zero will turn off the switch, non-zero will turn on the switch. Reading
the
PIO state will return the switch setting. To determine the actual
logic level at the switch, refer to the
sensed.0 sensed.1 sensed.ALL
sensed.BYTE property.
ALL references all channels simultaneously, comma separated.
BYTE references all channels simultaneously as a single byte. Channel 0
is bit 0.
power¶
read-only, yes-no
Is the
DS28E04 powered parasitically (=0) or separately on the Vcc pin
(=1)?
sensed.0 sensed.1 sensed.ALL sensed.BYTE¶
read-only, yes-no
Logic level at the
PIO pin. 0 = ground. 1 = high (~2.4V - 5V ). Really
makes sense only if the
PIO state is set to zero (off), else will read
zero.
ALL references all channels simultaneously, comma separated.
BYTE references all channels simultaneously as a single byte. Channel 0
is bit 0.
polarity¶
read-only, yes-no
Reports the state of the POL pin. The state of the POL pin specifies whether the
PIO pins P0 and P1 power up high or low. The polarity of a pulse generated at
a PIO pin is the opposite of the pin's power-up state.
- 0
- PIO powers up 0
- 1
- PIO powers up 1
por¶
read-write, yes-no
Specifies whether the device has performed power-on reset. This bit can only be
cleared to 0 under software control. As long as this bit is 1 the device will
allways respond to a conditional search.
set_alarm¶
read-write, integer unsigned (0-333)
A number consisting of 3 digits XYY, where:
- X
- select source and logical term
0 PIO OR
1 latch OR
2 PIO AND
3 latch AND
- Y
- select channel and polarity
0 Unselected (LOW)
1 Unselected (HIGH)
2 Selected LOW
3 Selected HIGH
All digits will be truncated to the 0-3 range. Leading zeroes are optional.
Low-order digit is channel 0.
Example:
- 133
- Responds on Conditional Search when latch.1 or latch.0 are set to 1.
- 222
- Responds on Conditional Search when sensed.1 and sensed.0 are set to
0.
- 000 (0)
- Never responds to Conditional Search.
STANDARD PROPERTIES¶
address¶
r_address¶
read-only, ascii
The entire 64-bit unique ID. Given as upper case hexidecimal digits (0-9A-F).
address starts with the
family code
r address is the
address in reverse order, which is often used in
other applications and labeling.
crc8¶
read-only, ascii
The 8-bit error correction portion. Uses cyclic redundancy check. Computed from
the preceding 56 bits of the unique ID number. Given as upper case hexidecimal
digits (0-9A-F).
family¶
read-only, ascii
The 8-bit family code. Unique to each
type of device. Given as upper case
hexidecimal digits (0-9A-F).
r_id¶
read-only, ascii
The 48-bit middle portion of the unique ID number. Does not include the family
code or CRC. Given as upper case hexidecimal digits (0-9A-F).
r id is the
id in reverse order, which is often used in other
applications and labeling.
locator¶
r_locator¶
read-only, ascii
Uses an extension of the 1-wire design from iButtonLink company that associated
1-wire physical connections with a unique 1-wire code. If the connection is
behind a
Link Locator the
locator will show a unique 8-byte number
(16 character hexidecimal) starting with family code FE.
If no
Link Locator is between the device and the master, the
locator field will be all FF.
r locator is the
locator in reverse order.
present (DEPRECATED)¶
read-only, yes-no
Is the device currently
present on the 1-wire bus?
type¶
read-only, ascii
Part name assigned by Dallas Semi. E.g.
DS2401 Alternative packaging
(iButton vs chip) will not be distiguished.
ALARMS¶
Use the
set_alarm property to set the alarm triggering criteria.
DESCRIPTION¶
1-Wire¶
1-wire is a wiring protocol and series of devices designed and
manufactured by Dallas Semiconductor, Inc. The bus is a low-power low-speed
low-connector scheme where the data line can also provide power.
Each device is uniquely and unalterably numbered during manufacture. There are a
wide variety of devices, including memory, sensors (humidity, temperature,
voltage, contact, current), switches, timers and data loggers. More complex
devices (like thermocouple sensors) can be built with these basic devices.
There are also 1-wire devices that have encryption included.
The 1-wire scheme uses a single
bus master and multiple
slaves on
the same wire. The bus master initiates all communication. The slaves can be
individually discovered and addressed using their unique ID.
Bus masters come in a variety of configurations including serial, parallel, i2c,
network or USB adapters.
OWFS design¶
OWFS is a suite of programs that designed to make the 1-wire bus and its
devices easily accessible. The underlying priciple is to create a virtual
filesystem, with the unique ID being the directory, and the individual
properties of the device are represented as simple files that can be read and
written.
Details of the individual slave or master design are hidden behind a consistent
interface. The goal is to provide an easy set of tools for a software designer
to create monitoring or control applications. There are some performance
enhancements in the implementation, including data caching, parallel access to
bus masters, and aggregation of device communication. Still the fundemental
goal has been ease of use, flexibility and correctness rather than speed.
DS28E04¶
The
DS28E04 (3) is a memory chip that bends the unique addressing
capabilities of the
1-wire design. Some of the ID bits can be assigned
by hardware.
ADDRESSING¶
All 1-wire devices are factory assigned a unique 64-bit address. This address is
of the form:
- Family Code
- 8 bits
- Address
- 48 bits
- CRC
- 8 bits
Addressing under OWFS is in hexidecimal, of form:
- 01.123456789ABC
where
01 is an example 8-bit family code, and
12345678ABC is an
example 48 bit address.
The dot is optional, and the CRC code can included. If included, it must be
correct.
DATASHEET¶
http://pdfserv.maxim-ic.com/en/ds/DS28E04.pdf
SEE ALSO¶
Programs¶
owfs (1) owhttpd (1) owftpd (1) owserver (1) owdir (1) owread (1)
owwrite (1) owpresent (1) owtap (1)
Configuration and testing¶
owfs (5) owtap (1) owmon (1)
Language bindings¶
owtcl (3) owperl (3) owcapi (3)
Clocks¶
DS1427 (3) DS1904(3) DS1994 (3) DS2404 (3) DS2404S (3) DS2415 (3) DS2417
(3)
DS2401 (3) DS2411 (3) DS1990A (3)
Memory¶
DS1982 (3) DS1985 (3) DS1986 (3) DS1991 (3) DS1992 (3) DS1993 (3) DS1995 (3)
DS1996 (3) DS2430A (3) DS2431 (3) DS2433 (3) DS2502 (3) DS2506 (3) DS28E04 (3)
DS28EC20 (3)
Switches¶
DS2405 (3) DS2406 (3) DS2408 (3) DS2409 (3) DS2413 (3) DS28EA00 (3)
Temperature¶
DS1822 (3) DS1825 (3) DS1820 (3) DS18B20 (3) DS18S20 (3) DS1920 (3) DS1921
(3) DS1821 (3) DS28EA00 (3) DS28E04 (3) EDS0064 (3) EDS0065 (3) EDS0066 (3)
EDS0067 (3) EDS0068 (3) EDS0071 (3) EDS0072 (3) MAX31826 (3)
Humidity¶
DS1922 (3) DS2438 (3) EDS0065 (3) EDS0068 (3)
Voltage¶
DS2450 (3)
Resistance¶
DS2890 (3)
Multifunction (current, voltage, temperature)¶
DS2436 (3) DS2437 (3) DS2438 (3) DS2751 (3) DS2755 (3) DS2756 (3) DS2760 (3)
DS2770 (3) DS2780 (3) DS2781 (3) DS2788 (3) DS2784 (3)
Counter¶
DS2423 (3)
LCD Screen¶
LCD (3) DS2408 (3)
Crypto¶
DS1977 (3)
Pressure¶
DS2406 (3) TAI8570 EDS0066 (3) EDS0068 (3)
Moisture¶
EEEF (3) DS2438 (3)
AVAILABILITY¶
http://www.owfs.org
AUTHOR¶
Paul Alfille (paul.alfille@gmail.com)