We are designing a board that has the Wiznet5500 as a communications module. In an earlier version of this same board we used the 5100 without any problem, but changing to the new module is not working as expected.
Our schematic is the following
What happens is that, although the signals sent by the uC by SPI are valid (MOSI, SCK, SS) the module does not respond at all in the MISO. We have also tried to bypass the MISO buffer with the same results.
Another thing that happens is that as soon as the board is powered, the two LEDs of the magjack turn on, both the ACT and the LINK, but it does not link if connected to a computer or a switch.
We understand that they are two separate problems. (Link and SPI)
Here I leave a picture of the real circuit:
And here the layout of the PCB on both sides:
We have also verified that we have a 14Mhz signal on the INT line
This same fault is proven in the 20 PCBs that we have ordered to manufacture. Manufacturing has been done in a factory with sufficient quality controls and is the only part of the system that is giving faults.
We are using as magjack the L836-1J1T-43, which is not one of the recommended ones, but which works correctly in another design with an ENC28J60. Could this be a problem?
The oscillator is the LFXTAL010595Cutt
The PCB also has a SPI header attached to the same pins. If in that header we connect the official wiznet w5500 Arduino shield, it works correctly.
Can you give us a hand to determine what may be happening, please?
Thank you so much. Regards: