RM0319 datasheet(170/368 Pages) STMICROELECTRONICS

170 / 368 page

Fast Ethernet ports (RMII0/RMII1/MII1)

RM0319

170/368

Doc ID 022640 Rev 3

The sequence above shows the beginning of an Ethernet frame. Byte order of transmission

is from top to bottom as shown. For a successful match to specific address 1, the following

address matching registers must be set up:

Base address + 0x98 0x87654321 (Bottom)

Base address + 0x9C 0x0000CBA9 (Top)

And for a successful match to the Type ID register the following should be set up:

Base address + 0xB8 0x00004321

See IEEE Standard 802-2001, Clause 9 for a detailed description of 802 addressing.

Broadcast address

The broadcast address of 0xFFFFFFFFFFFF is recognised if the no broadcast bit in the

network configuration register is zero.

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.

The unicast hash enable and the multicast hash enable bits in the network configuration

to a 6 bit index into the 64 bit hash register using the following hash function. The hash

function is an XOR 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 will be matched

according to whether the frame is multicast or unicast.

A multicast match will be 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.

A unicast match will be signalled if the unicast hash enable bit is set. da[0] is 0 and the hash

RM0319 датащи(PDF) 170 Page - STMicroelectronics