pub const MIN_MHR_SIZE: usize = 9;
Expand description

These constants are used for interacting with the SPI buffer, which contains a 1-byte SPI command, a 1-byte PHY header, and then the 802.15.4 frame. In theory, the number of extra bytes in front of the frame can depend on the particular method used to communicate with the radio, but we leave this as a constant in this generic trait for now.

Furthermore, the minimum MHR size assumes that

  • The source PAN ID is omitted
  • There is no auxiliary security header
  • There are no IEs
+---------+-----+-----+-------------+-----+
| SPI com | PHR | MHR | MAC payload | MFR |
+---------+-----+-----+-------------+-----+
\______ Static buffer rx/txed to SPI _____/
                \__ PSDU / frame length __/
\___ 2 bytes ___/