
PRS28.4G
IBM Packet Routing Switch
Internal Registers
Page 76 of 131
prs28.03.fm
August 31, 2000
5.2.20 Table Pointer Register
Reserved
T
Table Pointer Register
Upper Byte
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
Reset Value
0
OCM Address
14‘x’
Access Type
Read/Write
Bits
Description
Upper Byte
0 - 6
Reserved
.
7
Table Select
. Specifies the type of table, either Memory Row or Look-Up Table, to access:
0:
Memory Row access
1:
Look-Up Table access
Lower Byte, with Table Select = 0 (Memory Row Access)
8 - 10
Reserved
.
11 - 15
Byte Pointer
. Specifies the byte index of the Table Data register Upper Byte in the Memory Row Register.
The value range of this bit is 0 to 18. Since the Table Data register returns two bytes, only even values of the
Byte Pointer are allowed.
The value of this register is auto incremented by two after every access (read or write) to the Table Data
Register when Table Select = ‘0’b.
Bit 15 is always forced to 0.
Lower Byte, with Table Select = 1 (Look-Up Table Access)
8 to 10
Reserved.
11
Master/Slave Select
. Identifies the Look-Up Table. When ‘0’b, the master lookup table is selected. When
‘1’b, the slave lookup table is selected.
12 to 15
Look-Up Table Pointer
. Specifies the byte index of the Table Data register Upper Byte in the Look-Up
Table. The value range for these bits is 0 to 14. Since the Table Data register returns two bytes, only even
value of the Byte Pointer are allowed.
The value of this register is auto incremented by two after every access (read or write) to the Table Data
Register when Table Select = ‘0’b.
Bit 15 is always forced to 0.