I use two externl 4ch MUXs with AD7172-2 to get 8ch ADC system.
AD7172-2 setting is as follows
ch0(Ain0-Ain1) and ch1(Ain2-Ain3) enabled.
MUX_IO is set and GPIO0, GPIO1 are used to switch external 4ch MUXs.
use continuous conversion mode.
How does the channel sequencer switch ch0, ch1 and external MUXs with GPIOs ?
in the data sheet of AD7172-2, explanation of MUX_IO says:
This bit allows the ADC to control an external multiplexer, using GPIO0/GPIO1
in sync with the internal channel sequencing.
The analog input pins used for a channel can still be selected on a per channel basis.
Therefore, it is possible to have a 4-channel multiplexer in front of AIN0/AIN1 and
another in front of AIN2/AIN3, giving a total of eight differential channels with the AD7172-2.
However, only four channels at a time can be automatically sequenced.
A delay can be inserted after switching an external multiplexer (see the delay bits in the ADC Mode Register section).
"""However, only four channels at a time can be automatically sequenced."""
What does this means ?
Do I need to do something to switch from ch0 to ch1 ?