I have been working on a project that is an expansion of the Webclient example. I want to control and monitor some external devices with a webpage interface. I have been able to accomplish this task with minimal issues by using a WIZ811MJ Ethernet controller dev board connected to my uno. However, due to various reason I have decided to create my own Ethernet shield to mimic the WIZ811MJ. The schematic for my design can be seen in the first attachment.
To test my custom Ethernet shield I used the exact same code that worked with my WIZ811MJ. Upon testing my custom Ethernet shield I wasn’t even able to ping my system. I believe the issue resides with the SPI communication. After further tests I believe I have pinpointed the problem to the MISO line. The SCLK, MOSI, and SCS line all behave as expected. However, if you look at my second attachment of an oscilloscope plot the MISO line does not behave as expected (the orange plot is the MOSI line, and the blue plot is the MISO line) Instead of switching between two voltages levels like the MOSI line the MISO line stays at a constant voltage with some 4MHz noise.
Has anyone ever faced a similar issue or is anyone able to give me some pointers on how to solve this problem?