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NXP PCA9571
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The NXP PCA9571 chip is an 8-bits I²C output expander.

Details:
https://www.nxp.com/products/analog/interfaces/ic-bus/ic-general-purpose-i-o/remote-8-bit-general-purpose-outputs-for-1-mhz-i2c-bus:PCA9571
https://www.nxp.com/docs/en/data-sheet/PCA9571.pdf


Logic analyzer setup
--------------------

The logic analyzer used was a Hobby Components HCTEST0006 (at 2 MHz):

  Probe       I²C signal
  ----------------------
  0           SDA
  1           SCL


Data
----

The sigrok command line used was:

sigrok-cli -d fx2lafw -c samplerate=2mhz --time <time> \
	--channels 'D0=SDA,D1=SCL' -o <filename.sr>


This is a set of example captures of NXP PCA9571 I/O accesses.

Three traces are included:

 - pca9571_simple.sr: a simple output write operation.

 - pca9571_sequence.sr: 64 consecutive write operations.

 - pca9571_warning.sr: this produces a warning because the first read value
   is different from the expected one (the PCA9571 start-up 8-bits port
   status is high logic level 0xFF). This may occur if the first monitored
   operation is a read operation and the PCA9571 is not in its default state
   or if the PCA9571 reboots during the monitoring.