DS75

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O.S. OUTPUT TRANSFER FUNCTION Figure 2

Regardless of the mode chosen, the O.S. output is open–drain and the active state is set in the configura-

tion register. The power–up default is active low. Refer to the “OPERATION–Programming” section for

instructions in adjusting the thermostat setpoints, thermostat mode, and O.S. active state.

OPERATION–Programming

location. Table 3 illustrates the pointer settings for the four registers of the DS75.

Pointer Register Structure Table 3

POINTER

ACTIVE REGISTER

00h

Temperature (default)

01h

Configuration

02h

03h

The DS75 will power up with the temperature register selected. If the host wishes to change the data

pointer, it simply addresses the DS75 in the write mode (R/W=0), receives an acknowledge, and writes

the 8 bits that correspond to the new desired location. The last pointer location is always maintained so

that consecutive reads from the same register do not require the host to always provide a pointer address.

The only exception is at power–up, in which case the pointer will always be set to 00h, the temperature

register. The pointer address must always proceed data in writing to a register, regardless of which

address is currently selected. Please refer to the “2–Wire Serial Data Bus” section for details of the 2–

wire bus protocol.