NXP Semiconductors

MPL115A1S

Miniature SPI digital barometer, 50 kPa to 115 kPa

8 Functional description

aaa-044102

Reading

coefficient data

Initial

powerup

Data

conversion

Shutdown

Compensated

pressure reading

Figure 3. Sequence flowchart

The MPL115A interfaces to a host (or system) microcontroller in the user’s application. All communications are

via SPI. A typical usage sequence is as follows:

Initial power-up

All circuit elements are active. SPI port pins are high impedance and associated registers are cleared. The

device then enters Standby mode.

Reading coefficient data

The user then typically accesses the part and reads the coefficient data. The main circuits within the client

device are disabled during read activity. The coefficients are usually stored in the host microcontroller local

memory but can be re-read at any time.

Reading of the coefficients may be executed only once and the values stored in the host microcontroller. It is not

necessary to read this multiple times because the coefficients within a device are constant and do not change.

However, note that the coefficients are different from device to device, and cannot be used for another part.

Data conversion

This is the first step that is performed each time a new pressure reading is required which is initiated by the

host sending the CONVERT command. The main system circuits are activated (wake) in response to the

command and after the conversion completes, the result is placed into the Pressure and Temperature ADC

output registers.

The conversion completes within the maximum conversion time, tc (see row 6, in Table 11). The device then

enters Standby mode.

MPL115A1S

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Product data sheet

Rev. 1.2 — 8 May 2023

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