Conflict with IridiumSBD I2C library and SerialUSB (Qwiic Micro)

[adamgarbo]

Hi there,

I've encountered an issue when attempting to use a SparkFun Qwiic Micro with a RockBLOCK 9603 and the IridiumSBD I2C library. The issue is described in detail here: sparkfun/SparkFun_IridiumSBD_I2C_Arduino_Library#2

To summarize, the u-blox library is defining all instances of Serial as SerialUSB. However, the Qwiic Micro (one of the SerialUSB boards) uses Serial to connect to the RockBLOCK but this is being overwritten by the u-blox library as SerialUSB.

Commenting out line 63 resolves the issue:

SparkFun_Ublox_Arduino_Library/src/SparkFun_Ublox_Arduino_Library.h

Line 63 in 97bd455

#define Serial SerialUSB // Define Serial as SerialUSB

Cheers,
Adam

[PaulZC]

Hi Adam (@adamgarbo),
Thanks for finding this!
I suspect that if we change this line, the issue will go away...
I'll run some tests.
Cheers,
Paul

[PaulZC]

Hi Adam,
I'm not completely happy with this proposed fix - it is inelegant but seems to do the trick. Can you please test it?
75eedde
Many thanks,
Paul

[adamgarbo]

Hi @PaulZC,

The fix appears to resolve the issue. In the case of the Qwiic Micro, it looks like SerialUSB will either need to be used explicitly, or a serial port definition other than Serial will need to be used (e.g. #define SERIAL_PORT SerialUSB).

I'd be curious to learn more about how the Arduino compiler and how it handles conflicting #define statements. If it was done in order, the two define statements below should in theory work. I don't think it's that simple, though!

#define Serial SerialUSB
#define IridiumSerial Serial

Cheers,
Adam