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MPC8548 eTSEC truncated Tx frame exceeds MAXFRM

Question asked by Robert Bracero on Oct 26, 2016
Latest reply on Jan 6, 2017 by Robert Bracero

During MPC8548 Ethernet testing, we have observed that when a Tx frame is truncated, the eTSEC always sends exactly (MAXFRM + 5) bytes. It doesn’t matter how many bytes over MAXFRM you were trying to send (1, 1000, etc…). Looking at the extra 5 bytes, the first one is an extra valid data byte from the transmit buffer (i.e. txbuf[MAXFRM]). The last 4 look random. They are not data and they are not a valid CRC. Is this the expected MPC8548 eTSEC behavior?

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