Can a CM3 in a TP1 identify what node/slot it’s in...
# │forumt
Teslamax
11/13/2023, 6:30 PMI’m curious if the CM3’s in my Turing Pi 1 could identify what slot they’re in, perhaps by querying the Ethernet switch chip?
r
rlpm
04/28/2024, 3:26 AMGood question. I know the switch is on the i2c bus, but I haven't found a spec for that interface to see what it offers. You could add some jumpers to three GPIOs for each slot, encoded which slots is which. Then the Pi could read those GPIOs to determine which slot it's in.
t
Teslamax
04/29/2024, 3:14 AMinteresting idea!
Teslamax
04/29/2024, 3:15 AMsomeone once posted that some Ethernet switches support reporting the port number to other devices, but I forgot the exact terminology for it
Teslamax
04/29/2024, 3:22 AMChatGPT said it was "LLDP"
Teslamax
04/29/2024, 3:24 AMThe Turing Pi 1 uses the Realtek RTL8370NB-CG and it doesn't explicitly support LLDP. (per ChatGPT)
Teslamax
04/29/2024, 3:25 AMThe Turing Pi 2 uses the Realtek RTL8370MB-CG and it does support LLDP.
Teslamax
04/29/2024, 3:26 AMso, I may be out of luck in querying the switch itself...
r
rlpm
04/29/2024, 3:45 AMOoh, ask it what the Realtek RTL8370NB-CG supports over i2c?
rlpm
04/30/2024, 4:00 PMI've verified that if you shut down a CM3+ (running latest Raspbian Bookworm 64-bit lite), it will blink the corresponding activity LED on the TP1 a few times as it's going down, then will be lit for 500ms or so, then go out.
And CM4S with same OS will leave the LED on after being shut down.
You could use this to determine which CM is in which slot. Well, as long as you're willing to shut them down. 😉
I just did this in sequence for the 28 CMs in my BrambleBeast, to ensure the hostnames matched the board & slot numbers I expected. 👍
t
Teslamax
05/01/2024, 7:32 AMI was having issues with ChatGPT, think my pihole needed the domain whitelisted for some reason
Teslamax
05/01/2024, 7:38 AMChatGPT structured the answer like this:
Copy code
Here are some typical features and capabilities that can be accessed via the I2C interface on this chip:Teslamax
05/01/2024, 7:38 AM Copy code
The specific implementation and capabilities of the I2C interface on the Realtek RTL8370NB-CG may vary based on the switch's firmware and the requirements of the network environment. Typically, external controllers or management systems would interact with the chip via I2C to enable these features and integrate the switch into larger network management solutions.Teslamax
05/01/2024, 8:04 AMso, it doesn't really know and has no explicit info; but it's commentary was very well structured albeit speculative
Teslamax
05/05/2024, 1:38 AMBut ChatGPT’s been wrong before, I think the TP1 uses the *RTL8370-GR*…
r
rlpm
05/05/2024, 1:16 PMWhaaaa? ChatGPT can be wrong? Tell me I'm not hallucinating! 😂
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