ww_uid¶

ww_uid lists the unique ids of a unit: a chip's factory id, a MAC address, an EUI-64. One trait implemented once can carry several, which one-trait-per-id could not (a trait cannot be implemented twice on one server).

#[ww_trait]
pub trait Uid {
    const IDS: MaxLen<RefVec<'i, UniqueId<'i>>, 4>;
}

IDS is a const item, served without a handler and read by a host once per connection. Ids are read from the chip at boot, so a server provides them as a fn (const_model = "IDS=fn", fn uid_ids(&self) -> MaxLen<RefVec<'_, UniqueId<'_>>, 4> for uid: Uid). At most 4 ids.

The primary id¶

The first id is the primary id. A device puts its hex (lower case, no separators) into the USB serial number string and a host shows it in ww list. When the unit reboots into a ROM bootloader that reports the same id (RP2350 BOOTSEL, STM32 DFU) the host finds it again by it; see follow reboot.

UniqueId¶

• kind: UidKind - ChipUnique, Mac48, Eui64, Uuid, Other(name).
• source: UidSource - InternalIc, ExternalIc, Firmware, HardwareStraps, Other(name).
• value - up to 16 bytes.

Both enums are public and evolvable: a variant from a newer version reads as Unknown(u32).