Changes

=== Receiving ===

=== Receiving ===

The CP2200/1 appears to give access to the entire 64-byte (minimum) packet, which would include everything on the above diagram except for the "Preamble and Start Frame Delimiter".  The CP2200/1 can be programmed to filter out any packets not addressed to it, but it only verifies the first 5 bytes of the MAC address, which is useless, given that out system would likely be equipped with a single batch of controllers, differing only in the last octet of their MAC address. For good packets the FPGA can strip away and ignore the first 14 bytes (it does not need the length field, as we define our own standard for the packets below, using the first two data bytes to specify intended physical address and packet type.)  From there the FPGA can parse the data field according to the specifications outlined below.

The CP2200/1 appears to give access to the entire 64-byte (minimum) packet, which would include everything on the above diagram except for the "Preamble and Start Frame Delimiter".  The CP2200/1 can be programmed to filter out any packets not addressed to it, but it only verifies the first 5 bytes of the MAC address, which is useless, given that our system would likely be instrumented from a consecutive factory batch of controllers, perhaps differing only in the last octet of their MAC address. Manual filtering is necessary to create a proper filter. For good, standards-compliant packets the FPGA can strip away and ignore the first 14 bytes (e.g. it does not need the length field, as we define our own standard for the packets below, using the first two data bytes to specify intended physical address and packet type.)  From there the FPGA can parse the data field according to the specifications outlined below.

 

== Packets from the PC to the FPGA ==

== Packets from the PC to the FPGA ==