Macro shared_bus::new_cortexm

macro_rules! new_cortexm {
    ($bus_type:ty = $bus:expr) => { ... };
}

Macro for creating a Cortex-M bus manager with 'static lifetime.

This macro is a convenience helper for creating a bus manager that lives for the 'static lifetime an thus can be safely shared across tasks/execution contexts (like interrupts).

This macro is only available with the cortex-m feature.

Syntax

let bus = shared_bus::new_cortexm!(<Full Bus Type Signature> = <bus>).unwrap();

The macro returns an Option which will be Some(&'static bus_manager) on the first run and None afterwards. This is necessary to uphold safety around the inner static variable.

Example

static mut SHARED_DEVICE:
    Option<MyDevice<shared_bus::I2cProxy<shared_bus::CortexMMutex<SomeI2cBus>>>>
    = None;

fn main() -> ! {
    // For example:
    // let i2c = I2c::i2c1(dp.I2C1, (scl, sda), 90.khz(), clocks, &mut rcc.apb1);

    // The bus is a 'static reference -> it lives forever and references can be
    // shared with other tasks.
    let bus: &'static _ = shared_bus::new_cortexm!(SomeI2cBus = i2c).unwrap();

    let mut proxy1 = bus.acquire_i2c();
    let my_device = MyDevice::new(bus.acquire_i2c());

    unsafe {
        SHARED_DEVICE = Some(my_device);
    }

    cortex_m::asm::dmb();

    // enable the interrupt

    loop {
        proxy1.write(0x39, &[0xaa]);
    }
}

fn INTERRUPT() {
    let dev = unsafe {SHARED_DEVICE.as_mut().unwrap()};

    dev.do_something_on_the_bus();
}