I have a Raspberry Pi running on Android Things. I'm trying to send data that is over 8 bytes over a UART connection using the Pin 4 with a TTL through USB2.0. But that didn't work, so, should I be using some other pin like Pin 6? Or what should I be doing if I want to send a 9-byte data or 234212441325454543595674859764 to USB to TTL with pin 4?