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-------------------------------------------------------------------------------
NXP PCA9571
-------------------------------------------------------------------------------
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.
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