I plan to get and use a uConsole with LTE with CM5 with a USB SSD. Here’s why I’m wondering how much power the USB-A port provides:
I’ve been testing an SSD that I already have with a regular Raspberry 5 and I noticed: 1. using a USB2 port and max_usb_current=1 in /boot/usercfg.txt it runs stable for hours, 2. using a USB2 port without that setting it runs extremely unstable and disconnects after minutes, 3. using a USB3 port without that setting it runs somewhat badly and eventually disconnects every few hours.
Since I plan to use it as a system disk, a disconnect would be a big problem.
Hence I’m wondering, what power draw would the uConsole likely allow from its USB-A port, that I’ve heard limits to USB2 transfer speeds? If the LTE modem is also running? And does the above usercfg setting have any effect at all? I imagine it doesn’t just depend on the batteries?
I imagine if the uConsole port supplies at least 1A this SSD might work, and below perhaps not so much. Update: some sources I’ve found suggest up to 1.5A might be needed, hm.
Unmodified the uConsole will not boot from USB. There are some new adapter boards coming out from community members that that will be a option but they will also have NVME so you might want to use that instead of USB.
I have a 512GB USB drive internal in my uConsole now and I never get disconnects. Could maybe be a cable issue with yours?
The uConsole is known to have some weak USB stock. It gets overloaded and reset all USB devices.
I’m not booting from USB, just running the system disk from USB. So do you know any power draw numbers? The adapter board slot would be used up by LTE.
Sorry I don’t know any exact numbers but I do know on a stock uConsole my USB capture card will bring the USB down. The same capture card won’t do that with my CM5 in a IO board.
Then I’m surprised an SSD works for you at all. Or I guess my SSD is weird, but it seems to be average to below average when it comes to power draw in the real world reviews I’ve seen. Sadly, I haven’t found too many promising ways yet to get it to perhaps run slower.
I have my USB drive inside the case off the hackergadgets expansion boards internal port. It has some beefy capacitors on it and I can use my capture card in all the USBs on that expansion card.
TPS2553(U502) is powered by the TPS61178 (U102), which provides a 5V rail(SYS_5V) for the entire system, including the CM, LCD and modem.
But the keyboard is powered by the same TPS2553, and that is problem.
According to the datasheet “USB requirement that downstream facing ports are bypassed with at least 120 uF per hub”, but VBUS is shared between Type-A port (J503) and internal USB port, aka “keyboard” port (J502), аnd has only one capacitor with a capacity of 100uF (C513). It can be assumed that this is why the keyboard turns off when devices are plugged into the USB port.
>Is it will be reduced by modem or keyboard?
Modem - probably not, keyboard - no, it has negligible power consumption. Compute module is the main consumer, everything depends on it. For example, the RK3588S consumes about 2.8A in peak. Most likely, the USB-A port can provide it’s 1A.
Just in case: The TPS61178 is set to a maximum current of 9.7A
So the modem doesn’t share the same USB power source? Since I think on paper, the Quectel modems are USB devices as well.
In any case, I’ve reached out to some of the case vendors to get some info on how to throttle SSDs. Perhaps that would make it more workable if possible.
Do you know if this will be reduced by whatever the keyboard and LTE modem need, or separate?