KeithRB:
We need all your code. Are you using Serial or Software Serial for your reading?You should be able to just create your own buffer, read characters until you see a '$' and then read from the device into your buffer. No need to have the serial port buffer everything.
All the code would be way too long to paste. I am using Serial.
holmes4:
All (lower case) string in c are terminated by a null char '\0' . Your not doing this so println if goofing up. you also need to take car of the linefeed char.Mark
In the device schematics it specifically says the NMEA sentence is terminated with a (which is why I have the switch statement). The NMEA port is constantly printing (every second), it never stops. I'm unsure what println you are referring to, the only println in this function is the debug messages.
PaulS:
nmea_port looks like a SoftwareSerial instance. If it wasn't, it would be named Serial, Serial1, etc. Changing the size of the hardware serial buffer is going to have no impact on the SoftwareSerial buffer size. And, in general, is the wrong answer. Reading more frequently is.
I am using hardware serial.
#define terminal Serial
#define nmea_port Serial2
#define command_port Serial3