This guide is meant to explain how to upgrade the the ClearFog Pro to support both CN9130 SOM and A388 SOM.
25MHz reference clocks for Ethernet Switch and PHY
Dis-/Assemble the components from table below:
# | RefDes | Action | Comments |
1 | R140 | Remove | resistor 220Ω |
2 | R141 | Remove | resistor 499Ω |
3 | C52, C55 | Add | capacitor 22pF |
4 | Y1 | Add | crystal 25MHz |
5 | R138 | Remove | resistor 220Ω |
6 | R139 | Remove | resistor 499Ω |
7 | C154, C158 | Add | capacitor 22pF |
8 | Y2 | Add | crystal 25MHz |
The components locations are marked green / red in the pictures below:
Components side
Print Side
Impact
CN9130 SoM does not provide a 25MHz reference clock output, The changes outlined disconnect the SoM reference clock signal and replace it with crystals for both ethernet switch and port 6 phy.