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11 years, 3 months ago.
Please help me with MPL3115A2 pressure sensor
Can anybody help me writing some code for MPL3115A2 sensor? I tried for 3 days to make this sensor works but i have no results on mbed. All i need it's just data from 3 registers 0x01, 0x02, 0x03 in pressure mode (0x26 - CTRL-REG1 set for pressure mode). without conversion in temp, just bytes date and I will make the conversion. On arduino it's work just fine. Here is the link with documentations: https://www.sparkfun.com/products/11084 (also the working code for arduino can be found there).
2 Answers
11 years, 3 months ago.
The MPL3115A2 is a pressure/altitude sensor with I2C interface. It should operate on 3V3 and GND from mbed (pin40, pin1). It also needs I2C SDA and SCL (eg pin 9, 10). Normally I2C needs some pull-up Rs (4k7) to 3V3, the sparkfun board has those installed already.
The I2C slave address for the mbed libs is 0xC0.
Writing a byte to a register in the sensor is done like this:
char data[2]; data[0]=regAddr; //selects the register data[1]=value; //value written to the register i2c.write(0xC0, data, 2);
Reading a byte from the sensor is done like this:
char data[2]; data[0]=regAddr; //selects the register i2c.write(0xC0, data, 1, true); // last parameter indicates that a repeated start is needed for // the subsequent read operation i2c.read(0xC0, data, 1); //read from the selected register value=data[0];
thats indeed exactly what you need, you have to read the users manual of your sensor to see how he wants to be spoken to: if you have to send some commands to start measuring or if you can just read out some registers. try maybe with reading out some registers, dont matters which one, just to see if its working
char data[1]; data[0]=regAddr; //selects the register i2c.read(0xC0, data, 1); //read from the selected register
11 years, 3 months ago.
what kind of interface is it? try to look at other examples which work with this interface