Week 4 – Ethernet Layer
This week I started work on the network connections from the chip, mainly the ETHERNET communication from MCU to network. I was fairly new to the subject but not completely as I have completed my Data Communication module already, hence was familiar to the OSI model and other network conventions. However I soon came to realize that I was actually at the tip of the iceberg and just had the general knowledge of network connectivity.
I set out to research on the ETHERNET connection, and the TCPIP stack and was aided by the PIC18f97J60’s and PICDEM2.NET’s Datasheet which gave a thorough explanation of the PIC’s integrated Ethernet module and the on board Ethernet controller ENC28J60. Moreover I was supposed to use the PIC’s own Ethernet function so I focused on the TCP/IP stack provided by microchip.
The TCP/IP stack that is available from microchip consists of numerous function already compiled and made ready for user disposal. The PICDEM2.NET development board also comes with a demo application that demonstrates the correct usage of these functions for different applications. For the first few days I was studying the “PingDemo” code provided in order to get an idea of where to start.
Another source of assistance and one that is very beneficial is the AN833 – Microchip TCP/IP Stack Application Note which can also be downloaded at the microchip website. This documentation gives basic instruction on implementation and the usage of the different functions available.
My first task was to get the physical layer up and running before moving on to the other layers. The demo apps provided were not much of a help in initializing just the physical layer since it was filled up with application specific functions. However after referring to AN833 I came to the realization that just getting the link up and running required a just a few instructions calling the TCPIP Config. By the end of the week I had not got it up yet though.