Configuring FIFO mode in LIS3DH

[ramperry]

Posted on June 24, 2013 at 19:58

Hi,

   I am trying to configure LIS3DH in FIFO/Stream mode and have a few questions as the data sheet is not very clear.

1) Can I configure the INT2 as the WaterMark interrupt?  I don't see any option to configure INT2 as the interrupt in the register bits, although the spec seems to imply it is possible.  Our hardware has the INT2 pin connected to a GPIO, hence would like to know if configuring INT2 as the watermark interrupt is an option.

2) Since I couldn't configure INT2, I went with polling the WTM bit of FIFO_SRC_REG to see if the watermark threshold level has reached (assuming WTM bit is the place to look for).  However, whenever I read FIFO_SRC_REG it comes out as 0.  I have enabled the FIFO in CTRL_REG5 (bit 6) and set the mode in FIFO_CTRL_REG.  What am I missing? Also, FIFO_SRC_REG doesn't have any explanation on what the reg bits mean.

[ramperry]

Posted on June 24, 2013 at 21:52

Quick correction on point 2.

However, whenever I read FIFO_SRC_REG it comes out as 0x20 (not 0 as mentioned before).  FIFO seems to be empty.