No uBoot screen

Got new VisionFive2 rev 1.2A

no Boot screen.
flashed SD-Card, mounted Samsung 980Pro 1TB NVMe ssd
adjusted jumpers — can boot from SD but no luck with NVMe image (202306)
i assume i need to use the USB2TTL connector (part of the bundle) to displaying the boot messages. unfortunately there is nothing to be found in the docs on how to connecting. (the USB2TTL connector has 4 pins (green, black, red and white)

How do i see the bootup messages ?

To do this, please connect a second system to the UART of your VF2 using a 3.3V USB-to-serial converter or directly serial-to-serial as described here:

3.4.3. Using a USB to Serial Converter

Please connect only RXD, TXD and GND (as shown in Figure 3-10 Connecting Jumper Wire), never also 5V or 3.3V.


exactly there is my issue

I just have the USB2TTL cable which came with the bundle. but there is no doc on which color goes to which pin (i assume on GPIO).

Can you take a picture of the USB2TTL cable?

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it looks similar to: RPI USB TTL: Raspberry Pi - USB zu TTL, 0,9 m, PL2303HX bei reichelt elektronik

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These cheap cables are usually connected like this.

But a converter that works with 5V logic level must not be used to avoid damaging the GPIO!


which usb2ttl converter would you suggest ? I just find such ones on Amazon: Hailege 2pcs CP2102 USB 2.0 to TTL UART Serial Converter Module 5Pin STC PRGMR with Dupont Wire : Computer & Zubehör

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With serial (if it is 3.3 volt) it is safest to use only 3 wires ground(UART)==ground(VisionFive 2), TX(serial)=>RX(VF2) and RX(UART)<=TX(VF2).

It is best to never connect the voltage wire (+3.3 volt and especially not +5 volt), since the board is powered up already, and there is no way that the wire used could carry enough current to fully power up the board. And permanent damage will occur if the GPIO pins (except for the +5V) are accidentally connected to 5 volts.


The CP2102 is OK, I would maybe take this FT232RL.


I do not think that you need a serial cable (unless there is a problem), just upgrade firmware on the SPI NOR FLASH.


thank you so much. as it is always better to knowing what the hardware is capable/designed, i will order 1x Dtech and 1 AZDelivery CP2102 USB zu TTL Konverter HW-598 für 3,3V und 5V mit Jumper Kabel kompatibel mit Arduino inklusive E-Book! : Computer & Zubehör

should arrive aomewhen next week. i will wait until then before i come back with next question(s) if there are any.

again — Tthank you so much for helping out (as there is/was no documentation coming with the bioard. (should really be in the package)

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in principle you are right, but i do not see any u-Boot or SPI info, which i assume ican be seen when using the USB 2 TTK connection. before flashing, I’d prefer to see, whart is going om

that is/was the reason, why i was asking. there was no doc for the cable and I do not want to brick the board

Contact the seller for the exact pin out of the “USB2TTL connector (part of the bundle)”

Let’s say that the pin out is:

pin 1 3.3 Volt
pin 2 TXD
pin 3 RXD
pin 4 GND
pin 5 +5 Volt

It will probably be safe to use as long as you only connect 3 wires. That you never connect the first and last pin, because it could never provide enough current to power up the VF2.

VF2                  USB2TTL connector
6(ground)            pin 4 GND
8(UART TX 3.3v )     pin 3 RXD
10(UART RX 3.3v )    pin 2 TXD (needs to be 3.3v TTL)

But an even safer option, if you only want to see the output, would be to use only 2 wires (there is never any voltage generated by the USB2TTL connector entering the VF2 board, so even if the TX pin on the USB2TTL was 5 volt TTL it can not cause any damage, if it is not connected):

VF2                 USB2TTL connector
6(ground)            pin 4 GND
8(UART TX 3.3v )     pin 3 RXD

thanks for your help. works like charm

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