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TMP451-Q1

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SLOS877B – OCTOBER 2014 – REVISED JUNE 2019

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7.6.1.4 Configuration Register

The configuration register sets the temperature range, the ALERT/THERM modes, and controls the shutdown

mode. The configuration register is set by writing to pointer address 09h, and read by reading from pointer

address 03h. Table 6 summarizes the bits of configuration register.

Table 6. Configuration Register Bit Descriptions

CONFIGURATION REGISTER (READ = 03h, WRITE = 09h, POR = 00h)

BIT NUMBER

NAME

FUNCTION

POWER-ON RESET VALUE

7

MASK1

0 = ALERT Enabled

1 = ALERT Masked

0

6

SD

0 = Run

1 = Shut down

0

5

ALERT/THERM2

0 = ALERT

1 = THERM2

0

4:3

Reserved

—

0

2

RANGE

0 = 0°C to +127°C

1 = –64°C to +191°C

0

1:0

Reserved

—

0

MASK1 (bit 7) of the configuration register masks the ALERT output. If MASK1 is 0 (default), the ALERT output

is enabled. If MASK1 is set to 1, the ALERT output is disabled. This configuration applies only if the value of

ALERT/THERM2 (bit 5) is 0 (that is, pin 6 is configured as the ALERT output). If pin 6 is configured as the

THERM2 output, the value of the MASK1 bit has no effect.

The shutdown bit (SD, bit 6) enables or disables the temperature-measurement circuitry. If SD = 0 (default), the

TMP451-Q1 device converts continuously at the rate set in the conversion rate register. When SD is set to 1, the

TMP451-Q1 device stops converting when the current conversion sequence is complete and enters a shutdown

mode. When SD is set to 0 again, the TMP451-Q1 resumes continuous conversions. When SD = 1, a single

conversion can be started by writing to the one-shot start register. See the One-Shot Start Register section for

more information.

ALERT/THERM2 (bit 5) sets the configuration of pin 6. If the ALERT/THERM2 bit is 0 (default), then pin 6 is

configured as the ALERT output; if it is set to 1, then pin 6 is configured as the THERM2 output.

The temperature range is set by configuring RANGE (bit 2) of the configuration register. Setting this bit low

(default) configures the TMP451-Q1 device for the standard measurement range (0°C to 127°C); temperature

conversions are stored in the standard binary format. Setting bit 2 high configures the TMP451-Q1 device for the

extended measurement range (–64°C to 191°C); temperature conversions are stored in the extended binary

format (see Table 1).

The remaining bits of the configuration register are reserved and must always be set to 0. The power-on reset

value for this register is 00h.