65 lines
1.5 KiB
Rust
65 lines
1.5 KiB
Rust
//! Overriding an exception handler
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//!
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//! You can override an exception handler using the [`exception!`][1] macro.
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//!
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//! [1]: https://docs.rs/cortex-m-rt/0.5.0/cortex_m_rt/macro.exception.html
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//!
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//! ---
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#![deny(unsafe_code)]
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#![no_main]
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#![no_std]
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extern crate cortex_m;
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#[macro_use]
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extern crate cortex_m_rt as rt;
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extern crate cortex_m_semihosting as sh;
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extern crate panic_semihosting;
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use core::fmt::Write;
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use cortex_m::peripheral::syst::SystClkSource;
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use cortex_m::Peripherals;
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use rt::ExceptionFrame;
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use sh::hio::{self, HStdout};
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entry!(main);
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fn main() -> ! {
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let p = Peripherals::take().unwrap();
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let mut syst = p.SYST;
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// configures the system timer to trigger a SysTick exception every second
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syst.set_clock_source(SystClkSource::Core);
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syst.set_reload(8_000_000); // period = 1s
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syst.enable_counter();
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syst.enable_interrupt();
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loop {}
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}
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// try commenting out this line: you'll end in `default_handler` instead of in `sys_tick`
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exception!(SysTick, sys_tick, state: Option<HStdout> = None);
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fn sys_tick(state: &mut Option<HStdout>) {
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if state.is_none() {
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*state = Some(hio::hstdout().unwrap());
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}
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if let Some(hstdout) = state.as_mut() {
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hstdout.write_str(".").unwrap();
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}
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}
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exception!(HardFault, hard_fault);
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fn hard_fault(ef: &ExceptionFrame) -> ! {
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panic!("HardFault at {:#?}", ef);
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}
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exception!(*, default_handler);
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fn default_handler(irqn: i16) {
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panic!("Unhandled exception (IRQn = {})", irqn);
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}
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