This project is a combination of hardware, gateware and firmware for interfacing with 100BASE-FX SFP transceivers using an FPGA.
This project uses a custom designed Pmod for connecting SFP transceivers to FPGA development boards. More info available here.
The Physical Layer of the 7 layer OSI model is made up of multiple sub-layers which handle communication with the physical medium.
- Physical Medium Dependent (PMD)
- SFP transceiver converting between optical signalling and electrical signalling
- Physical Medium Attachment (PMA)
- NRZ-I Serialisation/Deserialisation
- Clock recovery from incoming signal
- Physical Coding Sublayer (PCS)
- Encoding/Decoding of 4b/5b symbols
- Media Independent Interface (MII)
- Connection of PCS to MAC
- Media Access Controller (MAC)
Most SFP transceivers include an I²C monitoring interface called Digital Diagnostics Monitoring (DDM) or Digital Optical Monitoring (DOM). A host device can retrieve information about the SFP such as manufacturer, model, serial number, temperature and optical levels through this interface.