112 lines
3.4 KiB
Rust
112 lines
3.4 KiB
Rust
#![no_std]
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#![no_main]
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use core::cell::RefCell;
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use core::ptr::read_volatile;
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use cortex_m::interrupt::Mutex;
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use panic_halt as _;
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use cortex_m_rt::{entry, exception};
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use cortex_m_semihosting::hprintln;
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use stm32f1::stm32f103;
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use stm32f1::stm32f103::interrupt;
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static mut SYS_TICK: u32 = 0;
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static I2C1: Mutex<RefCell<Option<stm32f103::I2C1>>> = Mutex::new(RefCell::new(None));
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fn get_sys_tick() -> u32 {
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unsafe { read_volatile(&raw const SYS_TICK) }
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}
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#[exception]
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fn SysTick() {
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unsafe { SYS_TICK += 1; }
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}
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fn toggle_mcu_led(gpioa: &mut stm32f103::GPIOA) {
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gpioa.odr.modify(|r, w| {
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match r.odr3().bit() {
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true => w.odr3().clear_bit(),
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false => w.odr3().set_bit(),
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}
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});
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}
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#[interrupt]
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fn I2C1_EV() {
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cortex_m::interrupt::free(|cs| {
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if let Some(ref mut i2c1) = *I2C1.borrow(cs).borrow_mut() {
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if i2c1.sr1.read().addr().bit_is_set() {
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let _ = i2c1.sr2.read();
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i2c1.dr.write(|w| w.dr().bits(0xAA));
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}
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}
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});
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}
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#[entry]
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fn main() -> ! {
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let peripherals = stm32f103::Peripherals::take().unwrap();
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let core_peripherals = cortex_m::Peripherals::take().unwrap();
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let mut syst = core_peripherals.SYST;
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let i2c1 = peripherals.I2C1;
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let mut gpioa = peripherals.GPIOA;
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// Enable Cortex-M SysTick
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peripherals.STK.ctrl.modify(|_,w| w.tickint().set_bit()); // Enable Systick Interrupt
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syst.set_reload(1_000 - 1); // Set period to 1ms
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syst.clear_current(); // Clear the current value register
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syst.enable_counter(); // Enable SysTick
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// Enable clock for GPIOA by setting IOPAEN in RCC APB2ENR
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peripherals.RCC.apb2enr.modify(|_, w| w.iopaen().set_bit());
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gpioa.crl.modify(|_, w| w.mode3().output());
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gpioa.crl.modify(|_, w| w.cnf3().push_pull());
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gpioa.odr.modify(|_, w| w.odr3().high());
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// Init i2c
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// Configure i2c clock
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peripherals.RCC.cfgr.modify(|_, w| w.ppre1().div2());
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peripherals.RCC.apb1enr.modify(|_, w| w.i2c1en().enabled());
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// Enable i2c clock
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peripherals.RCC.apb2enr.modify(|_,w| w.iopben().enabled());
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// Set GPIO pin configurations
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peripherals.GPIOB.crl.modify(|_,w| w.mode6().output50());
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peripherals.GPIOB.crl.modify(|_,w| w.mode7().output50());
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peripherals.GPIOB.crl.modify(|_,w| w.cnf6().alt_open_drain());
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peripherals.GPIOB.crl.modify(|_,w| w.cnf7().alt_open_drain());
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// Configure peripheral
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i2c1.cr1.modify(|_,w| w.pe().enabled());
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i2c1.cr1.modify(|_,w| w.smbus().i2c());
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i2c1.cr1.modify(|_, w| w.ack().set_bit());
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i2c1.oar1.modify(|_,w| w.add().bits(0x32 << 1));
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i2c1.oar1.modify(|_,w| w.addmode().add7());
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// Pass peripheral reference to global static
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cortex_m::interrupt::free(|cs| {
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i2c1.cr2.modify(|_,w| w.itevten().enabled());
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i2c1.cr2.modify(|_,w| w.itbufen().enabled());
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*I2C1.borrow(cs).borrow_mut() = Some(i2c1);
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// I don't understand why this is unsafe or how I could make it safe.
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unsafe { cortex_m::peripheral::NVIC::unmask(stm32f1::stm32f103::interrupt::I2C1_EV); }
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});
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let mut timer_ms = 500;
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loop {
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let current_value = get_sys_tick();
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if current_value >= timer_ms
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{
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toggle_mcu_led(&mut gpioa);
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timer_ms = current_value + 500;
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}
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}
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}
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