Hi. My project has a dependency that uses `Serial.dtr()`. Works fine when Serial is actually USB. Should build fine with MoteinoM0 since it supports SerialUSB.
However, moteino_zero/variant.cpp defines
Uart Serial( &sercom5, PIN_SERIAL_RX, PIN_SERIAL_TX, PAD_SERIAL_RX, PAD_SERIAL_TX ) ;
If I try to redefine `Serial` for the project to be `SerialUSB` (-DSerial=SerialUSB), I get a linker error stating that SerialUSB has been defined twice, because the line in variant.cpp has become
Uart SerialUSB( &sercom5, PIN_SERIAL_RX, PIN_SERIAL_TX, PAD_SERIAL_RX, PAD_SERIAL_TX ) ;
Is there a recommended way to build an entire project (source and dependencies) with a consistent definition of `Serial`?
If this is just broken, it seems like the right thing would be for variant.cpp to define this Uart as Serial5 (aligns with sercom5). Then `Serial` is available to be redefined as necessary. It could have a default #define Serial Serial5 so as not to break anybody. The adafruit/feather_m0 variant does this.
Thanks!
Hi frankleonrose,
I have not tried to do something like this via linker, I usually redefine Serial as SerialUSB with this directive, in the sketch itself:
#if defined(MOTEINO_M0) && defined(SERIAL_PORT_USBVIRTUAL)
#define Serial SERIAL_PORT_USBVIRTUAL // Required for Serial on Zero based boards
#endif
You could try to compile the same way in Arduino and see what you get.
The core follows the Arduino Zero (same MCU) pattern in terms of peripheral definitions.
I do not want to stray away from that standard since people expect it to work very similar to Arduino Zero.
My primary concern is being able to support this on the Arduino platform. Platformio is a niche that sometimes requires tweaking. So .. if Arduino Zero fails in the same manner, then I would raise an issue with Platform.io to look into it. If that escalates to be an Arduino core problem then Arduino should be flagged and if there is a resolution we can merge it in this M0 core.
Thanks, @felix.
I contributed a board specification (https://github.com/platformio/platform-atmelsam/commit/3c3c4ae8b39516b766b5cb1f81e7fac46702e40f) that should help other PlatformIO+MoteinoM0 users get started.
With respect to Serial, given the Arduino Zero standard and the fact that Arduino IDE doesn't offer project-wide defines (-DSOMETHING), the only solution is to avoid libraries that use Serial explicitly.
Thanks for the explanation and for making that contribution, I will follow that commit!