Freescale Semiconductor FRDM-FXS-MULTI-B Data Sheet

MPL3115A2

Sensors

Freescale Semiconductor, Inc.

Quick Start Setup

To set up the part in Altimeter mode, you may select your data retrieval method between polling (no FIFO), interrupt (no FIFO)

or with the FIFO.

The flow chart in

Figure 5

describes the setup for polling or interrupt with an OSR of 128.

Figure 6

describes the FIFO setup

with an OSR of 128.

See the application note titled Data Manipulation and Basic Settings of the MPL3115A2 Command Line Interface (document

AN4519).

Figure 5. Polling or Interrupt - No FIFO

Check for interrupt

on pin INT2

Poll data or use

interrupt INT2

Yes

Polling

/* Is SRC_DRDY Set */

(INT_S & 0x80) == TRUE

Service interrupt

and clear

Yes

Interrupt

/* Enable DRDY Interrupt */

IIC_RegWrite(SlaveAddressIIC, 0x29, 0x80);

/* Set Active */

IIC_RegWrite(SlaveAddressIIC, 0x26, 0xB9);

/* Enable Data Flags in PT_DATA_CFG */

IIC_RegWrite(SlaveAddressIIC, 0x13, 0x07);

/* I2C Address is 0xC0 */
SlaveAddressIIC = 0xC0

/* Set Active */

IIC _RegWrite(SlaveAddressIIC, 0x26, 0xB9);

/* Read STATUS Register */

STA = IIC _RegRead(SlaveAddressIIC, 0x00);

/* Is Data Ready */

(STA & 0x08) == TRUE

/* Read INT_SOURCE */

INT_S = IIC _RegRead(SlaveAddressIIC, 0x12);

/* Read OUT_P and OUT_T */

/* This clears the DRDY Interrupt */

OUT_P_MSB = IIC_RegRead(SlaveAddressIIC, 0x01);

OUT_P_CSB = IIC_RegRead(SlaveAddressIIC, 0x02);

OUT_P_LSB = IIC_RegRead(SlaveAddressIIC, 0x03);

OUT_T_MSB = IIC_RegRead(SlaveAddressIIC, 0x04);

OUT_T_LSB = IIC_RegRead(SlaveAddressIIC, 0x05);

Clear Interrupt

/* Read OUT_P and OUT_T */

/* This clears the DRDY Interrupt */

OUT_P_MSB = IIC_RegRead(SlaveAddressIIC, 0x01);

OUT_P_CSB = IIC_RegRead(SlaveAddressIIC, 0x02);

OUT_P_LSB = IIC_RegRead(SlaveAddressIIC, 0x03);

OUT_T_MSB = IIC_RegRead(SlaveAddressIIC, 0x04);

OUT_T_LSB = IIC_RegRead(SlaveAddressIIC, 0x05);

/* Set to Altimeter with an OSR = 128 */

IIC_RegWrite(SlaveAddressIIC, 0x26, 0xB8);

/* Set INT to Active Low Open Drain */

IIC_RegWrite(SlaveAddressIIC, 0x28, 0x11);