Bitcraze Forums

Good day,

I am working with the lighthouse deck for non-drone purposes and am therefore developing my own interface hardware.
According to the documentation, when using the external UART port (P3), the logic voltage must never exceed 3.2v.

My question is, does this apply to the other interfaces as well, such as I2C, UART1, etc?

Judging from the provided schematics, I do not see why it would be otherwise but the seed of doubt has already been planted.

I mainly ask this because I may have already ordered some PCBs and accidentally inverted the UART1 TX and RX pins meaning the voltage divider is on the wrong pin, requiring a reflash of the deck's bootloader to fix...

Best regards,
Alex

The FPGA on the lighthouse deck is a bit sensitive and we have managed to break some due to just applying 3.3V. So injecting any voltage above 3.2V on any pin seams dangerous.

A possible solution would be to exchange the 3.0V regulator (U2, TLV70230) to a 3.3V one on the lighthouse deck if you are using 3.3V on you interfacing board.

Thank you for your reply,

It seems the ideal in my case would be to avoid any hardware modifications and flash a new bootloader with the two pins inverted to ensure no overvoltage issues, rather than attempt to source regulators for a reasonable price...

I do find it bizarre that the FPGA would fail so easily considering that 3.3v falls well into the recommended operating conditions.

• VCCIO1,2,3 - min 1.71v - max 3.46v

That being said, I do not have any tangible experience with FPGAs and I am therefore assuming that the issue is with the single-ended DC electrical characteristics which states a max voltage of VCCIO+0.2v for all IO standards, hence your suggestion to replace the regulator.