A:
DIO-48D-LPE is designed to accept only byte access (8 bits access) .
On the other hands, The module before Ndivia TX2 supports only aligned access of Double Word through PCI Express bus.
Therefore, The module before Ndivia TX2 does not support unaligned access.
Unfortunately, Jetson Nano which is used on DX-U1100P1 is elder than Nvidia TX2 SoC module.
Therefore, You may not read the status of DIO-48D-LPE on DX-U1100P1.
Please consider to use the later model like DX-U1200P1 or DX-U1220P1 instead of DX-U1100P1.
The SoC module of these models are Jetson Xavier NX which supports aligned access of Double Word through PCI Express bus.
Please refer the following link to know more information from Ndivia.
[PCIE spurious interrupts]
https://forums.developer.nvidia.com/t/pcie-spurious-interrupts/116128/10