build fails with stm32h7xx_hal

[Flydroid]

Hi @marius-meissner ,

I was happy to find that there is already a create implementing the LTC681x family.
I'm working on a BMS based on the Portenta H7 development board
and cell sensor board with two LTC6812 ICs.

I have a working simple test code with spi in this commit: 1e2885d

When I add the LTC681x create like this commit b954de7 the build fails with the message:

error: no global memory allocator found but one is required; link to std or add `#[global_allocator]` to 
a static item that implements the GlobalAlloc trait

This shouldn't happen as the LTC681x crate is not using any alloc(), right?
I tried to check the heapless create, but except in its tests it also not using the std allocator.
Then maybe an interaction with the STM32H7xx_hal create?

Any hints or suggestions on how to fix this issue would be very appreciated!

[Flydroid]

I managed to get unstuck, by removing extern crate alloc from the lib.rs source.

After that of course the tests don't compile anymore.
In my project I must be missing something that suppresses that the test code gets compiled

[marius-meissner]

@Flydroid Thanks a lot for brining this up.
Shouldn't be a big deal for fixing this.
Could you please check if #7 viable solution?

[Flydroid]

@marius-meissner Thanks for the quick fix!
Yes it solves the build issue!