I have been trying to interface a GP-14198 unit to an older NMEA 0183 interface (on a yacht).
The interface requires a baud rate of 4800, but the GPS default UART baud rate is 9600.
I managed to change the GPS board rate using the test code supplied by u-blox and a TTL-USB interface
(Tx and Rx levels were 3.3 V; power supplied to GPS was 5 V).
The system is now spitting out NMEA sentences at 4800 baud.
However, the RMC sentence has a GN prefix (it is a GNSS unit after all), but I believe the system I am interfacing it to requires a GP prefix.
Whilst the u-blox evaluation code should allow me to enable this sentence, it seems I have now lost the ability to talk to the GPS via the UART.
In addition, I am seeing a sentence in the output that suggests the UART Rx is constantly being disabled:
$GNTXT,01,01,01,More than 100 frame errors, UART RX was disabled*70
So, I now cant change anything on the unit.
In addition, the unit has a compass on board, but data from it are not appearing on the UART output.
There is something being spat out on the I2C line (address 0x0D), but I am unsure how to interpret it.
The CP-14198 data sheet indicates that I2C is for factory programming.
The unit has a mixed provenance: it is a EPPINNO board, packaged and sold by ADH-Technology Co. (author of the data sheet) and is apparently based on a u-blox8 chip (so should accept UBX commands).
Could you please suggest how I can:
Restore the Rx input so that I can send the unit UBX commands and/or use the I2C interface for programming
Read the output from the QMC5883 compass
Could you also recommend an application I can use to program the unit.