Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Data Sheet
Product codes
AT91SAM9M10-G45-EK
734
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
• Base address + 0xB8 0x00004321
36.4.7
Broadcast Address
The broadcast address of 0xFFFFFFFFFFFF is recognized if the ‘no broadcast’ bit in the network configuration
register is zero.
register is zero.
36.4.8
Hash Addressing
The hash address register is 64 bits long and takes up two locations in the memory map. The least significant bits
are stored in hash register bottom and the most significant bits in hash register top.
are stored in hash register bottom and the most significant bits in hash register top.
The unicast hash enable and the multicast hash enable bits in the network configuration register enable the recep-
tion of hash matched frames. The destination address is reduced to a 6-bit index into the 64-bit hash register using
the following hash function. The hash function is an
tion of hash matched frames. The destination address is reduced to a 6-bit index into the 64-bit hash register using
the following hash function. The hash function is an
exclusive or
of every sixth bit of the destination address.
hash_index[5] = da[5] ^ da[11] ^ da[17] ^ da[23] ^ da[29] ^ da[35] ^ da[41] ^ da[47]
hash_index[4] = da[4] ^ da[10] ^ da[16] ^ da[22] ^ da[28] ^ da[34] ^ da[40] ^ da[46]
hash_index[3] = da[3] ^ da[09] ^ da[15] ^ da[21] ^ da[27] ^ da[33] ^ da[39] ^ da[45]
hash_index[2] = da[2] ^ da[08] ^ da[14] ^ da[20] ^ da[26] ^ da[32] ^ da[38] ^ da[44]
hash_index[1] = da[1] ^ da[07] ^ da[13] ^ da[19] ^ da[25] ^ da[31] ^ da[37] ^ da[43]
hash_index[0] = da[0] ^ da[06] ^ da[12] ^ da[18] ^ da[24] ^ da[30] ^ da[36] ^ da[42]
da[0]
represents the least significant bit of the first byte received, that is, the multicast/unicast indicator, and
da[47]
represents the most significant bit of the last byte received.
If the hash index points to a bit that is set in the hash register, then the frame is matched according to whether the
frame is multicast or unicast.
frame is multicast or unicast.
A multicast match is signalled if the multicast hash enable bit is set. da[0] is 1 and the hash index points to a bit set
in the hash register.
in the hash register.
A unicast match is signalled if the unicast hash enable bit is set. da[0] is 0 and the hash index points to a bit set in
the hash register.
the hash register.
To receive all multicast frames, the hash register should be set with all ones and the multicast hash enable bit
should be set in the network configuration register.
should be set in the network configuration register.
36.4.9
Copy All Frames (or Promiscuous Mode)
If the copy all frames bit is set in the network configuration register, then all non-errored frames are copied to mem-
ory. For example, frames that are too long, too short, or have FCS errors or rx_er asserted during reception are
discarded and all others are received. Frames with FCS errors are copied to memory if bit 19 in the network config-
uration register is set.
ory. For example, frames that are too long, too short, or have FCS errors or rx_er asserted during reception are
discarded and all others are received. Frames with FCS errors are copied to memory if bit 19 in the network config-
uration register is set.
36.4.10
Type ID Checking
The contents of the type_id register are compared against the length/type ID of received frames (i.e., bytes 13 and
14). Bit 22 in the receive buffer descriptor status is set if there is a match. The reset state of this register is zero
which is unlikely to match the length/type ID of any valid Ethernet frame.
14). Bit 22 in the receive buffer descriptor status is set if there is a match. The reset state of this register is zero
which is unlikely to match the length/type ID of any valid Ethernet frame.
Note:
A type ID match does not affect whether a frame is copied to memory.