You need a PoE mezzanine which communicates with the switch to enable power. The mezzanine is responsible for electro-isolation and downconverting the 48V DC down to to 5V AC. Mezzanines designed by our distributors will be available at the end of November.
1 Like
The AML-A311D-CC Alta and the AML-S905D3-CC Solitude are apparently available for preorder from LoveRPI: link
What is the recommended power supply size (Amps/Watts) for the new Cottonwood boards?
Without any USB peripherals or HATs:
Solitude needs 1A max.
Alta needs 2A max.
Is there an upper limit on the power supply size that these boards can make use of when peripherals are attached? For example, is there a benefit to selecting a 4A, 5A, or larger power supply? Or is there a maximum that these boards can draw through the USB-C connector that would make a larger power supply pointless?
I believe the Pi people have created some non-standard power delivery profile for their Raspberry Pi 5 that works with 5V @ 5A. When they detect a power supply that supports this profile, they allow additional power for the USB ports and HATs.
Knowing that Libre prefers to stick with standards as much as possible, I’m going to guess you didn’t do anything strange like that, but wanted to be certain.
From what I have read on the Power Delivery Standard, 3A (15W) is the highest standard power profile available for 5V. But, I also know there are a number of 5V/4A USB-C Power Supplies available on the market.
See the schematics. This board does not negotiate PD profiles for 5A but can use more than 3A if needed and if the power supply is willing to supply without negotiation. The USB ports are fused for 1A each so USB devices alone can use 4A backed by a 5A MOSFET.
You are going to get severe ohmic losses on your past 3A on most cables and components so it is unwise to design something like the Raspberry Pi 5 where you’re using 5A. If you compare the Raspberry Pi 5’s design to Alta’s design, you will see that Pi relies on PMIC where as Alta uses discrete components. Raspberry Pi traded simplicity for fundamental design problems as seen previously on the Raspberry Pi 3 low power issues.
Using discrete components for Alta is more complex and requires more care but you get benefits like better heat dissipation, more power, better impedance matching, and faster circuit response. Alta is able to handle high power devices much better than Raspberry Pi 5 simply because it doesn’t have 5V5A going through a tiny component, much like Le Potato handles high power devices much better than Raspberry Pi 3 with the same power supply.
There are advanced PMICs that together with selective discrete components can offer the best overall design in terms of cost and performance but you’re looking at more advanced and power hungry solutions in the hundreds of dollars. For a low power and low cost SBC, use a PMIC if your power supply is 12V. Avoid it like hell if your power supply is 5V and you need > 3A like on the Raspberry Pi boards since Pi 3. It is just bad news.
2 Likes
Are the usb fuses regular fuses or are they reset on power toggle? i forget what those fuses are called.
You can check the part number on the schematic for the datasheet.
Are you suggesting that the attached image is sufficient to explain what kind of fuses are being used? I’m just going to assume that the worst case scenario fuses are being used, or simply, the usb port is basically permanently unusable if any device exceeds 1a. FUSE-0805 means nothing, 0805 is the chip size, not a part number. 6F1 is also not seen anywhere else on the schematic, and a parts list is not provided that correlates with these 6XX identifiers. I think I’ll look elsewhere for my project since the response from the official team is basically google it.
USB ports fuses are standard self-resetable fuse. We use the same ones on various boards with different trip points. In this case, it is a standard 1A fuse that can come from a few manufacturers.
Hi, any news on the PoE mezzanine ?
The design has been completed by our affiliate. It’s awaiting manufacturing after CNY.
Does this mean that even though the pin-out of the Alta appears to mirror the pin-out of RPF 3B+ that the PoE boards compatible with RPF 3B+ should not be used with the Alta board?
We have not tested with the Pi 3 B+ HAT but the UART headers should conflict with it. Our partners are designing a 25W HAT for Alta.
In the meantime I have a board advertised to support PoE, but no way to use PoE! I guess I’ll sacrifice a $40 Solitude board to testing myself. I’m specifically interested in whether a Uctronics UC-775 will work as I plan to rack-mount a few of the boards. The stock heat-sink will need to go as its too tall, but shouldn’t be an issue replacing a lower profile heat-sink as the PoE board has a fan.
Hi all!
Yes I was really excited about getting the Alta but now I am frustrated a bit. Extra 25 bucks not a lot but what I have got for it? I tried both latest Debian and latest Armbian OS for ARM.
There is no specific versions for A311D, it is recommended here the version that supports UEFI BIOS., OK maybe, one fits all and UEFI OS should support NPU since Librecomputer site linked to OS vendors such as Debian and Armbian.Nop. There does not support NPU of Alta in these. The way to check? Easy. The OS that supports NPU should have the file galcore.ko somewhere in the /usr/lib directory tree. Using >find -name gallcore.ko brings no result. It means there is no support for NPU in the OS? To be honest, Armbian does support other SBC’s with A311D since people are saying they found galcore.ko in installed OS for bananapi SBC. But that OS does not start on Alta, probably wrong BIOS? So it seems Armbian supports some SBC’s NPU’s as per each, while advertising those SBC’s in their web site, but there is no single word about Alta there. Sad.
- You can use our +arm64 UEFI images per the instructions on the download page for the product.
- galcore.ko is the proprietary Verisilicon implementation, not the open source Mesa implementation that we support. We do not support the proprietary implementation.
- Armbian is a community project. They cut and paste code and binaries that are open and closed source from all over the place. There are licensing, testing, and long term maintenance issues with such a work model.
Thank you very much for your response! Will work with Mesa,
In fact, already have figured that. My next issue is that after enabling the NPU with Libre Wiring Tool my HDMI console dies. Even in headless version of Debian 12. Need to figure way to connect over serial port? I can see despite the console dead the Ethernet lights are active blinking means not everything dead, it is just HDMI perhaps.
Robotics noob reporting for duty!
- I’m using ROS2+OpenCV for object tracking, what NPU is available on the Alta and how can I determine if OpenCV can use it.
1.1 How can I configure OpenCV to use the NPU? - Where can I get detailed info on the device-tree overlays? what are their function/applications?
- cpu-b-opp-2304
- cpu-l-opp-2208
- spifc-nor
Thanks