It seems like their would be an issue with connecting an FTDI cable such as the SparkFun “FTDI Cable 5V” to the UART 2 pin outs on the F9P GPS board. I presume the board is outputting 3.3V on the VCC pin and I assume the FTDI cable is outputting 5V on the same pin. Would it be correct to just use header pins on the GPS board with the VCC pin cut off (such that the two VCCs remain unconnected)?
Hi Daveb100,
A short answer is no, a 5V FTDI would not work directly connected to the UART2 on the ZED-F9P Breakout. The issue here is not just the supply voltage but also the logic level voltage of the UART2 (and all ports on the ZED-F9P) is 3.3V. Connecting a device like a 5V FTDI cable directly to those pins can damage them since the logic HIGH for the FTDI is 5V. You will either want to use a [level shifter or switch to a 3.3V FTDI cable. Lastly, just in case you were considering using UART2 for serial commands, it’s really only there for RTCM correction data. UART1 is the best option for receiving data and controlling the ZED-F9P via serial.](https://www.sparkfun.com/categories/361)