I’m using an Au V2. If I connect a Fn V2 it results in “No board detected.” when plugged in to the pc. Without the fan connected it’s fine and I can program Au V2’s RAM and Flash. When the fan is connected, the fan doesn’t spin. All LEDs on the main board flash on and off with the power LED swapping between red and green.
Did I get a bad Fn V2?
Hello,
That sounds like a surge or short circuit somewhere on the Fn.
The power stage turns on, and immediately cut-off when the surge is detected. Hence the boot loop and blinking.
The issue could comes from the Fn PCB, the fan itself, or a damaged connector.
I would suggest not using the Fn and wait for @alchitry answer, but you can try to inspect it and see if there is a visible issue, like a bad solder or a bent pin in a connector.
It could be a bent pin on the Au side of the connector too.
I wonder if a too long cable and/or weak USB port or bad USB contact could also cause voltage drop when the fan tries to spin up?
I’ve seen this issue. It happens from the voltage on the USB port dropping below 4.5V and triggering an under voltage lock out.
You can get around it by reducing the voltage drop on the USB port (lower resistance cable) or removing a resistor on the back of the board to disable UVLO. The current batch of Pt/Au being made have the UVLO disabled as this seems to be more annoying than helpful.
This is the resistor to remove.
Fantastic! Thank you both. I removed the resistor and all is well.
I’m currently moving a large-ish project from Vivado/Verilog (Different board/chip) to Lab/Lucid with HDMI and a CPU/GPU, so the fan is a must as the chip does get hot.
Thank you again.
