embassy/embassy-stm32/src/uid.rs
2024-03-20 16:39:09 +01:00

32 lines
1.0 KiB
Rust

//! Unique ID (UID)
/// Get this device's unique 96-bit ID.
pub fn uid() -> &'static [u8; 12] {
unsafe { &*crate::pac::UID.uid(0).as_ptr().cast::<[u8; 12]>() }
}
/// Get this device's unique 96-bit ID, encoded into a string of 24 hexadecimal ASCII digits.
pub fn uid_hex() -> &'static str {
unsafe { core::str::from_utf8_unchecked(uid_hex_bytes()) }
}
/// Get this device's unique 96-bit ID, encoded into 24 hexadecimal ASCII bytes.
pub fn uid_hex_bytes() -> &'static [u8; 24] {
const HEX: &[u8; 16] = b"0123456789ABCDEF";
static mut UID_HEX: [u8; 24] = [0; 24];
static mut LOADED: bool = false;
critical_section::with(|_| unsafe {
if !LOADED {
let uid = uid();
for (idx, v) in uid.iter().enumerate() {
let lo = v & 0x0f;
let hi = (v & 0xf0) >> 4;
UID_HEX[idx * 2] = HEX[hi as usize];
UID_HEX[idx * 2 + 1] = HEX[lo as usize];
}
LOADED = true;
}
});
unsafe { &*core::ptr::addr_of!(UID_HEX) }
}