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FXLS8471Q - SPI communication

Question asked by Leonardo Gabrich on Aug 14, 2016
Latest reply on Aug 22, 2016 by Leonardo Gabrich

Hello,

I'm having some trouble to configure the SPI communication in FXLS8471Q accelerometer.

I'll need to get the data to each second, so, to do that, i configure a interrupt timer to send a request to read WHO_I_AM register each 1 sec, but reading the MISO pin with oscilloscope i've got this stranger signal.  

Sinal acelerometro.jpg

But, changing the time that interrupt occurs for about 30us I get the correct signal, but i get the data more times than i need. 

Another problem is that the accelerometer's configuration is very unstable. Sometimes, the accelerometer is sending some data and, when I turn off the power and turn it again, it does not send any data.

I suspect that the selection of the accelerometer as SPI is giving an error. What does it mean MISO pin floating? He will receive different voltage values?

 

This is the  schematic:

Esquemático.png

The RST pin is welded to ground.

I'd like to know if someone has a code example of the accelerometer configuration as SPI using a microcontroller. I use a DSP TMS320F, then it don't has a library ready for accelerometer, like a breakout board has.

Well, the last question, what means to say that register is auto-incremented? This means that when I read the OUT_X_MSB register the device will send me OUT_X_MSB value, than OUT_X_LSB, OUT_Y_MSB and so on?

 

Thanks!!

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