6.7 Configuration of MCAN_NBTP.NTSEG2 = ’0’ not allowed

Attention: This erratum is applicable for CAN 2.0.

When MCAN_NBTP.NTSEG2 is configured to zero (Phase_Seg2(N) = 1), and when there is a pending transmission request, a dominant third bit of Intermission may cause the MCAN to wrongly transmit the first identifier bit dominant instead of recessive, even if this bit was configured as ’1’ in the MCAN’s Tx Buffer Element.

A phase buffer segment 2 of length ’1’ (Phase_Seg2(N) = 1) is not sufficient to switch to the first identifier bit after the sample point in Intermission where the dominant bit was detected.

The CAN protocol according to ISO 11898-1 defines that a dominant third bit of Intermission causes a pending transmission to be started immediately. The received dominant bit is handled as if the MCAN has transmitted a Start-of-Frame (SoF) bit.

The ISO 11898-1 specifies the minimum configuration range for Phase_Seg2(N) to be 2..8 tq. Therefore excluding a Phase_Seg2(N) of ’1’ will not affect MCAN conformance.

Work around

Use the range 1..127 for MCAN_NBTP.NTSEG2 instead of 0..127.