NXPMotionSense "config error MPL3115" when using NXP Precision 9DoF breakout board

Projects Programming
1

I'm trying to use the examples scrips in the NXPMotionSense library but I can't get it to work because it expects an MPL3115 altitude and temperature sensor despite it seemingly not being used for the orientation calculations.

I'm using an NXP Precision 9DoF FXOS8700+FXAS21002 breakout board, the library just expects the MPL3115 to also be there.

How do I get around this, is there a version of the library that excludes this sensor?

Cheers.

while (!FXOS8700_begin()) {
	Serial.println("config error FXOS8700");
	delay(1000);
}
while (!FXAS21002_begin()) {
	Serial.println("config error FXAS21002");
	delay(1000);
}
while (!MPL3115_begin()) {
	Serial.println("config error MPL3115");
	delay(1000);
}
2

I can't believe I got confused by this for 2 hours, and then 22 minutes after posting I figure out a work around, I'm gonna post the changes here in case anyone has the same issue.

I modified the two functions below from the NXPMotionSense.cpp file. I suppose I could have removed the sections that call them, but I don't know what kind of mischief that might cause.

bool NXPMotionSense::MPL3115_begin() // pressure
{
        const uint8_t i2c_addr=MPL3115_I2C_ADDR;
        uint8_t b;
		
	return true; // <-------------------------------------------------------- This pretends I have the sensor
	
	if (!read_regs(i2c_addr, MPL3115_WHO_AM_I, &b, 1)) return false;
	//Serial.printf("MPL3115 ID = %02X\n", b);
	if (b != 0xC4) return false;

	// place into standby mode
	if (!write_reg(i2c_addr, MPL3115_CTRL_REG1, 0)) return false;

	// switch to active, altimeter mode, 512 ms measurement, polling mode
	if (!write_reg(i2c_addr, MPL3115_CTRL_REG1, 0xB9)) return false;
	// enable events
	if (!write_reg(i2c_addr, MPL3115_PT_DATA_CFG, 0x07)) return false;

	//Serial.println("MPL3115 Configured");
	return true;
}

bool NXPMotionSense::MPL3115_read(int32_t *altitude, int16_t *temperature)
{
	static elapsedMicros usec_since;
	static int32_t usec_history=980000;
	const uint8_t i2c_addr=MPL3115_I2C_ADDR;
	uint8_t buf[6];
	
	return false; // <-------------------------------------------------------- This ignores the read request

	int32_t usec = usec_since;
	if (usec + 500 < usec_history) return false;

	if (!read_regs(i2c_addr, FXAS21002_STATUS, buf, 1)) return false;
	if (buf[0] == 0) return false;

	if (!read_regs(i2c_addr, buf, 6)) return false;

	usec_since -= usec;
	int diff = (usec - usec_history) >> 3;
	if (diff < -1000) diff = -1000;
	else if (diff > 1000) diff = 1000;
	usec_history += diff;

	int32_t a = ((uint32_t)buf[1] << 12) | ((uint16_t)buf[2] << 4) | (buf[3] >> 4);
	if (a & 0x00080000) a |= 0xFFF00000;
	*altitude = a;
	*temperature = (int16_t)((buf[4] << 8) | buf[5]);

	//Serial.printf("%02X %d %d: ", buf[0], usec, usec_history);
	//Serial.printf("%6d,%6d", a, *temperature);
	//Serial.println();
	return true;
}