Mark Butcher

ENET_RCR[PADEN] what effect does it have?

Discussion created by Mark Butcher on Sep 29, 2012

Hi All


The Ethernet controller in the Kinetis saves short frames (less that 60 bytes Ethernet payload) as padded frames of 60 bytes length (VLAN tagged and non-tagged frames are saved the same).


There is a description of the PADEN bit in the ENET_RCR register which seems to suggest that this padding can be removed by enabling it. Testing with short ARP frames on the network (42 bytes length) the receiver was reporting 60 bytes Ethernet payload whether this bit was set of not and storing zeroes to pad up to the 60 byte payload area end.


Have I misunderstood the function of the bit? and is there another methdi which will allow the frame to be saved as short frame?