MDS212 Datasheet, PDF (74/111 Pages) Zarlink Semiconductor Inc – 12-Port 10/100Mbps Ethernet Switch

Bit [27:23]
Count
MDS212
Data Sheet
Count = Burst Size in double words Burst size for internal
memory is up to 8 D-words. Burst size for external memory is up
to 16 D-words
00001 = 1 D-word, ……01000 = 8 D-word
01111 = 15 D-word 10000 = 16 D-word
Valid value range for internal memory is {1 to 8}
Valid value range for external memory is {1 to 16}
Caution: When setting Count = 16, the Starting address has to be in the Q-word boundary. That is MA[2]=0.
Bit [31:28]Reserved
18.2.3.4 Memory Read/Write Data Registers
• Four 32-bit data registers share a common format
• MWDR
Memory Write Data Register
• Access: Zero-Wait-State,
via FIFO,
Write only
• Address: h790
• MRDR
Memory Read Data Register
• Access: Zero-Wait-State,
Direct Access,
Read only
• Address: h794
• Byte Order depends on CPU types
• Little Endian CPUs
31
24 23
16 15
Byte[3]
Byte[2]
Byte[1]
87
0
Byte[0]
• Big Endian CPUs
31
24 23
16 15
Byte[0]
Byte[1]
Byte[2]
87
0
Byte[3]
18.2.3.5 VTB - VLAN ID Table Base Pointer
• Access:
• Address:
Non-Zero-Wait-State, Direct Access,
h798
Write/Read
31
17 16 15
11 10 9 8 7 6 5
0
VMACB
VLMS
VLAN ID BASE
Bit [5:0]
Bit [6]
Bit [8:7]
VIDB
Reserved
VLMS
VLAN ID Table Base, serves as [20:15]
bits of address. (VLAN ID Table is 32KB)
The size of VLAN MAC Table
00= reserved
01=16K (for 64 VLANs)
Default=11
10=32K (for 128 VLANs)
11=64K (for 256 VLANs)
74
Zarlink Semiconductor Inc.