Rainbow-electronics DS1620 Manual de usuario descargar pdf (Pagina 3)

DS1620

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TEMPERATURE MEASURING CIRCUITRY Figure 2

This calculation is done inside the DS1620 to provide 0.5°C resolution. The temperature reading is

provided in a 9–bit, two’s complement reading by issuing a READ TEMPERATURE command. Table 1

describes the exact relationship of output data to measured temperature. The data is transmitted serially

through the 3–wire serial interface, LSB first. The DS1620 can measure temperature over the range of

-55°C to +125°C in 0.5°C increments. For Fahrenheit usage, a lookup table or conversion factor must be

used.

TEMPERATURE/DATA RELATIONSHIPS Table 1

TEMP DIGITAL OUTPUT

(Binary)

DIGITAL OUTPUT

(Hex)

+125°C 0 11111010 00FA

+25°C 0 00110010 0032h

+½°C 0 00000001 0001h

+0°C 0 00000000 0000h

-½°C 1 11111111 01FFh

-25°C 1 11001110 01CEh

-55°C 1 10010010 0192h

Since data is transmitted over the 3–wire bus LSB first, temperature data can be written to/read from the

DS1620 as either a 9–bit word (taking RST low after the 9

(MSB) bit), or as two transfers of 8–bit

SLOPE ACCUMULATOR

PRESET COMPARE

LOW TEMPERATURE

COEFFICIENT OSCILLATOR

COUNTER PRESET

TEMPERATURE REGISTER

HIGH TEMPERATURE

COEFFICIENT OSCILLATOR

COUNTER

INC

STOP

SET/CLEAR

LSB

1 2 3 4 5 6 7 8 ... 12 13

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Rainbow-electronics DS1620 Manual de usuario Pagina 3