Is daisy chaining/series connection of for example two Nanos recommended? Meaning WAN into one nano, then another connection to the other nano. This would essentially leave us with 5 usable ports in the system, right?
Yes it’s possible and people do this pretty often. A couple things to bear in mind.
- GigaBlox (and, by extension GigaBlox Nano since it uses the same chip) have a bug related to this (see below). It’s easy to workaround, just use different numbered ports on each GigaBlox Nano.
- Connecting two ports together will result in a potential bottleneck. Imagine two ports on GigaBlox A want both want to send 1Gbps to two ports on GigaBlox B. This would require an aggregate data rate of 2Gbps to be sent across the daisy chain connection, but that daisy connection is only 1Gbps. This means packet loss. This very rare though, as most ports don’t come close to operating a full line rate for any length of time. But it is something to bear mind. More on this topic can be found in the forum post below.
- Connecting two GigaBlox Nano over together eats up a port on each, giving you six ports total to play with.
Let me know if that makes sense
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Reading ENT-AN0114 - SimpliPHY Transformerless Ethernet Designs, I see that they are recommending connecting two SimpliPHYs together using 100 Ohm diff traces through DC blocking capacitors.
Do you have any design recommendations having this section in mind for connecting two Nanos together? Should the Nanos be connected through caps? Any particular caps recommended?
The GigaBlox Nano module itself already integrates 0.1uF DC blocking capacitors on each track.
So, when you connect two GigaBlox Nano together, you end up with two 0.1uF capacitors on each line. This has very little effect on the signal and works perfectly well.
In other words, you don’t need to do anything, you can wire two GigaBlox Nano together directly.
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