|
|
PDF DS1629 Data sheet ( Hoja de datos )
| Número de pieza | DS1629 | |
| Descripción | 2-Wire Digital Thermometer and Real Time Clock | |
| Fabricantes | Dallas | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de DS1629 (archivo pdf) en la parte inferior de esta página. Total 22 Páginas | ||
|
No Preview Available !
www.dalsemi.com
DS1629
2-Wire Digital Thermometer
and Real Time Clock
FEATURES
§ Measures temperatures from -55°C to
+125°C; Fahrenheit equivalent is -67°F to
257°F
§ Real time clock counts seconds, minutes,
hours, date of the month, month, day of the
week, and year with leap year compensation
through the year 2100
§ Thermometer accuracy is ±2.0°C (typ)
§ Thermometer resolution is 9 bits (expandable)
§ Thermostatic and time alarm settings are user
definable. Dedicated open-drain Alarm output
§ 32 bytes SRAM for general data storage
§ Data is read from/written to via a 2-wire serial
interface. (open drain I/O lines)
§ Wide power supply range (2.2V - 5.5V)
§ Applications include personal
computers/PDAs, cellular telephones, office
equipment, dataloggers, or any thermally
sensitive system
§ 8-pin 150mil SOIC package
PIN ASSIGNMENT
SDA
SCL
ALRM
GND
1
2
3
4
8 VDD
7 OSC
6 X1
5 X2
DS1629S 8-Pin SOIC
(150-mil)
PIN DESCRIPTION
SDA
- 2-Wire Serial Data Input/Output
SCL - 2-Wire Serial Clock
GND
- Ground
ALRM
- Thermostat & Clock Alarm
Output
X1 - 32.768 kHz Crystal Input
X2 - 32.768 kHz Crystal Feedback
Output
OSC
- Buffered Oscillator Output
VDD - Power Supply Voltage (+2.2V to
+5V)
DESCRIPTION
The DS1629 2-Wire Digital Thermometer and Real Time Clock integrates the critical functions of a real
time clock and a temperature monitor in a small outline 8-pin SOIC package. Communication to the
DS1629 is accomplished via a 2-wire interface. The wide power supply range and minimal power
requirement of the DS1629 allow for accurate time/temperature measurements in battery-powered
applications.
The digital thermometer provides 9-bit temperature readings which indicate the temperature of the device.
No additional components are required; the device is truly a “temperature-to-digital” converter.
The clock/calendar provides seconds, minutes, hours, day, date of the month, day of the week, month, and
year. The end of the month date is automatically adjusted for months with less than 31 days, including
corrections for leap years. It operates in either a 12- or 24-hour format with AM/PM indicator in 12-hour
mode.The crystal oscillator frequency is internally divided, as specified by device configuration. An
open-drain output is provided that can be used as the oscillator input for a microcontroller.
1 of 22
102299
1 page  
DS1629
At the same time, the counter is then preset with a value determined by the slope accumulator circuitry.
This circuitry is needed to compensate for the parabolic behavior of the oscillators over temperature. The
counter is then clocked again until it reaches 0. If the gate period is still not finished, then this process
repeats.
The slope accumulator is used to compensate for the nonlinear behavior of the oscillators over
temperature, yielding a high resolution temperature measurement. This is done by changing the number
of counts necessary for the counter to go through for each incremental degree in temperature. To obtain
the desired resolution, therefore, both the value of the counter and the number of counts per degree C (the
value of the slope accumulator) at a given temperature must be known.
Internally, this calculation is done inside the DS1629 to provide 0.5°C resolution. Table 2 describes the
exact relationship of output data to measured temperature. For Fahrenheit usage, a lookup table or
conversion factor must be used.
Note that temperature is represented in the DS1629 in terms of a 0.5°C LSB, yielding the 9-bit format
illustrated in Table 2. Higher resolutions may be obtained by implementing the algorithm in Application
Note 105 and performing the following calculation. The 8-bit COUNT_REMAIN value can be obtained
via the Read Counter (A8h) command and the COUNT_PER_C value (also 8-bit) is read via the Read
Slope command (A9h).
T = TEMP_READ -0.25 + (COUNT_PER_C_COUNT_REMAIN)
COUNT_PER_C
Temperature/Data Relationships Table 2
S 26 25 24 23
MSb (unit = °C)
2-1 0 0 0 0
22
0
21 20 MSB
LSb
0 0 LSB
TEMPERATURE
+125°C
+25°C
0.5°C
0°C
-0.5°C
-25°C
-55°C
DIGITAL OUTPUT
(Binary)
01111101 00000000
00011001 00000000
00000000 10000000
00000000 00000000
11111111 10000000
11100111 00000000
11001001 00000000
DIGITAL OUTPUT
(Hex)
7D00h
1900
0080
0000
FF80
E700h
C900h
5 of 22
102299
5 Page 
DS1629
CAL = Clock Alarm Latch. This volatile status bit will be set to "1" when the clock comparator becomes
active. Once set, it will remain latched until DS1629 power is cycled. A "0" in this location indicates the
clock has never been in an alarm condition since the DS1629 was powered-up. This is a read-only bit
(writes to this location constitute a “don’t care”) and the power-up default is the flag cleared (CAL="0").
TAL = Thermal Alarm Latch. This volatile status bit will be set to "1" when the thermal comparator
becomes active. Once set, it will remain latched until DS1629 power is cycled. A "0" in this location
indicates the DS1629 temperature has never exceeded TH since power-up. This is a read-only bit (writes
to this location constitute a “don’t care”) and the power-up default is the flag cleared (TAL="0").
0 = Don’t care. "Don’t care" on a write, but will always read out as a "0".
2-WIRE SERIAL DATA BUS
The DS1629 supports a bi-directional two-wire bus and data transmission protocol. A device that sends
data onto the bus is defined as a transmitter, and a device receiving data as a receiver. The device that
controls the message is called a “master.” The devices that are controlled by the master are “slaves.” The
bus must be controlled by a master device which generates the serial clock (SCL), controls the bus access,
and generates the START and STOP conditions. The DS1629 operates as a slave on the 2-wire bus.
Connections to the bus are made via the open-drain I/O lines SDA and SCL.
The following bus protocol has been defined:
• Data transfer may be initiated only when the bus is not busy.
• During data transfer, the data line must remain stable whenever the clock line is HIGH. Changes in
the data line while the clock line is high will be interpreted as control signals.
Accordingly, the following bus conditions have been defined:
Bus not busy: Both data and clock lines remain HIGH.
Start data transfer: A change in the state of the data line, from HIGH to LOW, while the clock is HIGH,
defines a START condition.
Stop data transfer: A change in the state of the data line, from LOW to HIGH, while the clock line is
HIGH, defines the STOP condition.
Data valid: The state of the data line represents valid data when, after a START condition, the data line
is stable for the duration of the HIGH period of the clock signal. The data on the line must be changed
during the LOW period of the clock signal. There is one clock pulse per bit of data.
Each data transfer is initiated with a START condition and terminated with a STOP condition. The
number of data bytes transferred between START and STOP conditions is not limited, and is determined
by the master device. The information is transferred byte-wise and each receiver acknowledges with a 9th
bit.
The maximum clock rate of the DS1629 is 400 kHz.
11 of 22
102299
11 Page | ||
| Páginas | Total 22 Páginas | |
| PDF Descargar | [ Datasheet DS1629.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| DS1620 | Digital Thermometer and Thermostat | Dallas |
| DS1621 | Digital Thermometer and Thermostat | Dallas |
| DS1624 | Digital Thermometer and Memory | Dallas |
| DS1626 | High-Precision 3-Wire Digital Thermometer and Thermostat | Dallas |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |