MPL3115A2

Sensors

32

Freescale Semiconductor, Inc.

7.16

Maximum Temperature

7.16.1 T_MAX_MSB, T_MAX_LSB (0x24, 0x25)

Register with captured maximum temperature value.

The Temperature data is arranged as 12-bit 2’s complement value in degrees C. The 8 bits of T_MAX_MSB representing

degrees and with fractions of a degree stored in 4 bits in position 7-4 of T_MAX_LSB.

The register is cleared on power-up or manually by writing 0 to the registers

7.17

Control Registers

Note: Except for standby mode selection and OST (One Shot Mode), the device must be in STANDBY mode to change any

of the fields within CTRL_REG1 (0x26).

7.17.1 CTRL_REG1 (0x26)

Table 55. T_MAX_MSB Register

7

6543

21

0

R

T_MAX 11

T_MAX 10

T_MAX 9

T_MAX 8

T_MAX 7

T_MAX 6

T_MAX 5

T_MAX 4

W

Reset

0

0000

00

0

Table 56. T_MAX_LSB Register

7

6

5

43

210

R

T_MAX 3

T_MAX 2

T_MAX 1

T_MAX 0

0

000

W

Reset

0

0

0

00

000

Table 57. CTRL_REG1 Register

7

6

5

43

210

R

ALT

RAW

OS2

OS1

OS0

0

OST

SBYB

W

RST

Reset

0

0

0

00

000

Table 58. CTRL_REG1 Bit Descriptions

Name

Description

SBYB

This bit is sets the mode to ACTIVE, where the system will make measurements at periodic times based on the value of ST bits.

Default value: 0 (STANDBY)

0: Part is in STANDBY mode

1: Part is ACTIVE

OST

OST bit will initiate a measurement immediately. If the SBYB bit is set to active, setting the OST bit will initiate an immediate

measurement, the part will then return to acquiring data as per the setting of the ST bits in CTRL_REG2. In this mode, the OST

bit does not clear itself and must be cleared and set again to initiate another immediate measurement.

One Shot: When SBYB is 0, the OST bit is an auto-clear bit. When OST is set, the device initiates a measurement by going into

active mode. Once a Pressure/Altitude and Temperature measurement is completed, it clears the OST bit and comes back to

STANDBY mode. User shall read the value of the OST bit before writing to this bit again.

RST

Software Reset. This bit is used to activate the software reset. The Boot mechanism can be enabled in STANDBY and ACTIVE

mode.

When the Boot bit is enabled the boot mechanism resets all functional block registers and loads the respective internal registers

with default values.

If the system was already in STANDBY mode, the reboot process will immediately begin; else if the system was in ACTIVE

mode, the boot mechanism will automatically transition the system from ACTIVE mode to STANDBY mode, only then can the

reboot process begin.

At the end of the boot process the RST bit is de-asserted to 0. Reading this bit will return a value of zero.

Default value: 0

0: Device reset disabled

1: Device reset enabled