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DS Maxim Integrated Board Mount Temperature Sensors datasheet, inventory, & pricing. The DS Programmable Digital Thermostat provides a thermal alarm logic output when the temperature of the device exceeds a user-defined temperature. DS datasheet, DS pdf, DS data sheet, datasheet, data sheet, pdf, Dallas Semiconductor, Programmable Digital Thermostat.

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Power-on reset is achieved by capacitor C3 and resistor R4.

DS1821 Datasheet

Operating modes The DS has two operating modes: DS The DS 3 is a unique 1-wire device. At the heart of the circuit is the microcontroller AT89S, which controls all its functions.

When the set temperature is exceeded, the relay connected to port 3. These pins are pulled high through a kilo-ohm resistor.

AN #39 – Digital Thermometer-Cum controller with DS – MCS Electronics

See the datasheet for further information on thermostat mode. A special circuit is required – see the datasheet for complete details. Units for the temperature alarms are in the same temperature scale that was set for temperature measurements. If polarity is 0 the output is active low.


All communication on the single-wire bus is initiatised by the microcontroller, and issued by time slots of active-low on a normally-high DQ line, issued by the device, which is sending at the moment.

Single-side PCB layout for digital thermometer-cum-controller. It can operate as a standalone thermostat with user-programmable trip-points set-point or as an 8-bit temperature sensor with a single-wire digital interface.

When the microcontroller watches something happen with single-wire bus, it issues a reset command. There are a wide variety of devices, including memory, sensors humidity, temperature, voltage, contact, currentswitches, timers and data loggers.

Writing to these nonvolatile registers can take up to 10 ms. Also in this mode, the control unit can initiate ds8121 stop temperature measurements as described in the operation-measuring temperature section of the datasheet.

Define the various port pins and where they are connected. A 12MHz crystal is used for microcontroller clock. The source program is well commented for easy understanding. Dataheet in thermostat mode, it is no longer programmable from a 1-wire interface. An actual-size, single-side PCB for temperature controller Fig. In this mode, the DQ pin of the DS is configured as a singlewire port for communication with a microprocessor using the protocols described in the single-wire bus system section of the datasheet.


The internal capacitor of the device meets its power needs during the low time. The device is connected through contacts of RL1. Resistors R5 through R22 limit the current through the 7-segment display.

The signal from port pin P3. Details of the individual slave or master design are hidden behind a consistent interface. The bus master initiates all communication.

The preset counter value is unique for every temperature increment and compensates for the non-linear behaviour of the oscillators over temperature. Special electrical incantations on the power and data lines must be performed that are not possible with a normal 1-wire bus master. Note that alarms are not implemented.

This state persists across power cycles and operates in both 1-wire and thermostat modes. Switch S1 is used as a reset switch. Each device is uniquely and unalterably numbered during manufacture.