cortex_m/peripheral/itm.rs
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//! Instrumentation Trace Macrocell
//!
//! *NOTE* Not available on Armv6-M and Armv8-M Baseline.
use core::cell::UnsafeCell;
use core::ptr;
use volatile_register::{RO, RW, WO};
/// Register block
#[repr(C)]
pub struct RegisterBlock {
/// Stimulus Port
pub stim: [Stim; 256],
reserved0: [u32; 640],
/// Trace Enable
pub ter: [RW<u32>; 8],
reserved1: [u32; 8],
/// Trace Privilege
pub tpr: RW<u32>,
reserved2: [u32; 15],
/// Trace Control
pub tcr: RW<u32>,
reserved3: [u32; 75],
/// Lock Access
pub lar: WO<u32>,
/// Lock Status
pub lsr: RO<u32>,
}
/// Stimulus Port
pub struct Stim {
register: UnsafeCell<u32>,
}
impl Stim {
/// Writes an `u8` payload into the stimulus port
#[inline]
pub fn write_u8(&mut self, value: u8) {
unsafe { ptr::write_volatile(self.register.get() as *mut u8, value) }
}
/// Writes an `u16` payload into the stimulus port
#[inline]
pub fn write_u16(&mut self, value: u16) {
unsafe { ptr::write_volatile(self.register.get() as *mut u16, value) }
}
/// Writes an `u32` payload into the stimulus port
#[inline]
pub fn write_u32(&mut self, value: u32) {
unsafe { ptr::write_volatile(self.register.get(), value) }
}
/// Returns `true` if the stimulus port is ready to accept more data
#[cfg(not(armv8m))]
#[inline]
pub fn is_fifo_ready(&self) -> bool {
unsafe { ptr::read_volatile(self.register.get()) & 0b1 == 1 }
}
/// Returns `true` if the stimulus port is ready to accept more data
#[cfg(armv8m)]
#[inline]
pub fn is_fifo_ready(&self) -> bool {
// ARMv8-M adds a disabled bit; we indicate that we are ready to
// proceed with a stimulus write if the port is either ready (bit 0) or
// disabled (bit 1).
unsafe { ptr::read_volatile(self.register.get()) & 0b11 != 0 }
}
}