sealhat / lsm303 Goto Github PK

A function to enable the interrupt for the FIFO watermark.

• The function should return a standard error code or ERR_NONE
• The function should have minimal parameters if it can use the current state to choose settings

I2C bus throws many errors when working at 400kHz. seems to be very reliable at 200kHz.

• Test the speed limit as configured
• write code that can recover from a bus error
• use o-scope to try to detect bus problems

The watermark should dynamically adapt to the bus speed and latency of the system.

When the fifo is read if the the FIFO count is too close to overflowing, too far past the watermark, or an actual overflow (as some examples) the watermark could be lowered.

The watermark could be raised if the watermark is below some default and the count is the same as the watermark several times in a row.

This would not happen that often since changing the watermark is a whole I2C transaction.

The IMU should use the FIFO to read from the LSM303x.

• A function to enable or disable the FIFO. This should have minimal parameters since most settings can be derived from the current IMU mode.
• Watermark needs to be set at an appropriate level based on the current sample rate, bus speed, and interrupt latency, such that there are no overflows.
• The FIFO read function should have an interface similar to a standard unix read function.
  • A buffer is passed in and filled with the number of samples available up to the buffer size.
  • The function should return the number of samples read.
  • The function should never read more samples than are available.
  • The function should never read more samples than fit in the buffer.
  • The function should return some kind of error to indicate an overflow has occurred or not.

A function to enable the interrupt for the magnetometer data ready signal.

• The function should return a standard error code or ERR_NONE
• The function should have minimal parameters if it can use the current state to choose settings