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8e636f0d12
Some beginners are confused about the "extern" section, so I added an explanation comment to all examples. Furthermore, using the UARTx interrupts when UART is actually being used in the same example may be confusing, so I changed them all to SSI0/QEI0.
53 lines
1.6 KiB
Rust
53 lines
1.6 KiB
Rust
//! examples/schedule.rs
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#![deny(unsafe_code)]
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#![deny(warnings)]
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#![no_main]
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#![no_std]
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use cortex_m::peripheral::DWT;
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use cortex_m_semihosting::hprintln;
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use panic_halt as _;
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use rtic::cyccnt::{Instant, U32Ext as _};
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// NOTE: does NOT work on QEMU!
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#[rtic::app(device = lm3s6965, monotonic = rtic::cyccnt::CYCCNT)]
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const APP: () = {
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#[init(schedule = [foo, bar])]
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fn init(mut cx: init::Context) {
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// Initialize (enable) the monotonic timer (CYCCNT)
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cx.core.DCB.enable_trace();
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// required on Cortex-M7 devices that software lock the DWT (e.g. STM32F7)
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DWT::unlock();
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cx.core.DWT.enable_cycle_counter();
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// semantically, the monotonic timer is frozen at time "zero" during `init`
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// NOTE do *not* call `Instant::now` in this context; it will return a nonsense value
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let now = cx.start; // the start time of the system
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hprintln!("init @ {:?}", now).unwrap();
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// Schedule `foo` to run 8e6 cycles (clock cycles) in the future
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cx.schedule.foo(now + 8_000_000.cycles()).unwrap();
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// Schedule `bar` to run 4e6 cycles in the future
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cx.schedule.bar(now + 4_000_000.cycles()).unwrap();
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}
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#[task]
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fn foo(_: foo::Context) {
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hprintln!("foo @ {:?}", Instant::now()).unwrap();
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}
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#[task]
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fn bar(_: bar::Context) {
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hprintln!("bar @ {:?}", Instant::now()).unwrap();
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}
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// RTIC requires that unused interrupts are declared in an extern block when
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// using software tasks; these free interrupts will be used to dispatch the
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// software tasks.
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extern "C" {
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fn SSI0();
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}
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};
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