I currently have two LTC6820s connected with a twisted pair cable (one acting as m*ster connected to an LPC55S28 and the other as sl*ve connected to an LPS22HB Pressure sensor). In order to match the data sheet of the sensor, I have changed the CPHA pin of both isoSPI devices (SPI mode 2). I have two 2K resistors one from 3v3 to MOSI and the other from 3v3 to MISO on the slave LTC. The analogue and digital signals on the logic analyzer after sending the device WHO_AM_I are shown below.
The white signal is the 1MHz clock signal between the two m*ster devices whereas the yellow signal is between the sl*ve devices. These show an analogue sample rate of 10MHz. Why aren't both signals identical in amplitude? Since it does not reach zero/oscillate much, MOST of the time a digital signal is not recognised and the WHO_AM_I data (sent using MCUXpresso SDK) does not reach the sl*ve device far less anything being returned on the MISO.
SPI Blue - between the LPS55S28 and the m*ster LTC6820
SPI Green - between the LPS22HB and the sl*ve LTC6820
A0 - A7 => Corresponding analogue signals
I would really appreciate the assistance with the clock signal. Thanks in advance!