search

teemuatlut / TMC2130Stepper

Arduino library for Trinamic TMC2130 Stepper driver
MIT License
159 stars 50 forks source link

Got TMC2130Stepper library working after 'constexpr' compile errors with STM32 on Arduino IDE #54

Open loopyengineeringco opened 6 years ago

loopyengineeringco commented 6 years ago

Great library, thank you.

In Arduino 1.8.5 IDE, I tried to compile my code with TMC2130Stepper for my 'Blue Pill' STM32F103 (hardware support from stm32duino.com).

Ran into a load of compiler errors, pointing to the use of 'constexpr' in TMC2130Stepper_REGDEFS.h. I don't have the error log now, but it was something to do with compiler version not understading constexpr.

I replaced every instance of 'constexpr' with 'const' in TMC2130Stepper_REGDEFS.h, and it compiled fine and works fine.

I couldn't replicate this by installing the whole toolkit from fresh along with all the hardware definitions, boards, libraries on a new machine. This error doesn't show up. But it did on my older dev computer that's had incremental arduino updates for the last 5 years.

So just in case anyone's looking for this issue - it might help someone to get their prototype working.

Not sure about the actual implications of using const vs constexpr, maybe someone could explain?

teemuatlut commented 5 years ago

In a nutshell, constexpr means the value can be calculated and used in compile time. Sort of like type safe #define. Const just tells the compiler that the value will/should not be changed at any point, and you'll get a compile error if you try to do so. Const is more just for the developer's aid but a smart compiler can do some optimizations based on the keyword. A big difference is also where the values are placed in memory. A simple const will be placed in SRAM (unless otherwise instructed) while a constexpr will be placed in PROGMEM which we have plenty.

Without an error log I can't say much about using the library with STM32.

knutollebolle commented 5 years ago

I think I've got the same errors:

/Users/svenklein/Documents/Arduino/libraries/TMC2130Stepper/src/TMC2130Stepper_REGDEFS.h:33:11: error: 'uint8_t' does not name a type constexpr uint8_t REG_DCCTRL = 0x6E;

It will give this error on almost every line from the TMC2130Stepper_REGDEFS.h file. I'm working with Arduino 1.8.8 on a MacBook. I hope you can help me out, at the moment I'm not able to get my TMC2130 working on a MKS Gen L V1.0

knutollebolle commented 5 years ago

Problem solved, I had to take out the TMC2130Stepper.h from the header. No problems with compiling now.