AMDS docs: explain custom cabling needed to daisy chain two AMDS boards

[elsevers]

Context

Related Issues / PRs:

• Add AMDS firmware changes to implement the DCP AMDS#102
• Add Daisy Chain Protocol Documentation and instructions on how to build and flash #154
• Update AMDS docs to explain daisy chain protocol #163
• https://github.com/Severson-Group/nsf_pfi_bearingless/issues/652

We are updating the AMDC - AMDS link to support daisy chain, as documented in the related issues/PRs above. To connect two AMDS boards together, the TX and RX pins must be transposed in the cable.

Approach

Update the AMDS daisy chain doc to indicate how to obtain a custom cable. See this issue for the required pinout and an example of how to order these:

• https://github.com/Severson-Group/nsf_pfi_bearingless/issues/652