When Length/Type error checking is enabled, the following checks are made on all frames received. If either of these checks fails, the frame is dropped and a Receive Reject interrupt is activated (see bit 28 in Interrupt Status Register).
- A value greater than or equal to decimal 46 but less than decimal 1536 in the length/type field is checked against the actual data length received.
- A value less than decimal 46 in the length/type field is checked to ensure the data field is padded to exactly 46B. The resultant frame is now the minimum frame size: 64B total in length.
Additionally, if FCS passing is disabled, the length/type field is used to strip the FCS field and any padding that might exist. Neither is passed to you.