I am trying to receive GPS module's sent nmea data with stellaris launchpad. GPS's transmitter TX signal (CMOS level) is conneceted to Launhpad's uc's (lm4fh5qr) pin number 9 (configured to UART7 / Port PE0). Oscilloscopes picture shows GPS's serial mode signal connected to pin 9.
But in uart7's interrupt routine received nmea data is corrupted. And at the moment i am not able to debug launchpad at all. Error message is : Error connecting to the target: Frequency is out of range. After error message CCS5.3 crashes down.
1
Should i use pull-up resistor when connecting gps cmos level tx singal to uc's TTL level pin 9. Pin 9 is programmatically configured as serial input signal. Is there any knowledge how to adjust CMOS level output signal to Launchpad's TTL input signal.
Edit :
On my stellaris board header pin J2-PE0 is marked as J2-P30 ? Am i only one?