There is a PDF (2009) referenced in this post describing how to synchronize two AD7147 shield excitation signals:
However, there are several other posts indicating it is not possible (can't tell the original post dates or chip revision level as these posts were archived in 2016):
- Has anyone successfully used this sychronization technique in a design?
- Will the undocumented TEST CONTROL bit 4 in register 0x44 referred to in the PDF work on AD7147 chip rev E?
- This technique indicates an external clock is applied to the GPIO pin to synchronize the device shields. Is this clock to be at the ACShield frequency of 250kHz, or some other rate?