PXF4333 Datasheet, PDF (138/361 Pages) Infineon Technologies AG – ABM 3G ATM Buf fer Manager

5.4
External RAM Interfaces
ABM-3G
PXF 4333 V1.1
Interface Description
5.4.1 RAM Configurations
The ABM-3G device uses synchronous dynamic RAM (SDRAM) for the storage of ATM
cells and synchronous static RAM (SSRAM) for the storage of cell pointers. Two SDRAM
Interfaces and one SSRAM Interface are provided. Each of the two SDRAM Interfaces
is associated with one of the ABM Cores. The SSRAM Interface is shared by both
ABM-3G Cores. All RAM Interfaces are operated with the system clock provided by the
ABM-3G:
Table 5-9 External RAM Sizes
Cell Pointer
SSRAM
Min.
Required
Up-
stream Cell
SDRAM
Min.
Required
Down-
stream Cell
SDRAM
UBMTH Up-
stream
Buffer
DBMTH Down-
stream
Buffer
e.g.
128 Mb
512 k x 32 bit e.g.
128 Mb
e.g.
3FFFF_H 256K
cells
2*(4Mb*16) 2*(4Mb*16)
3FFFF_H 256K cells
e.g.
64 Mb
256 k x 32 bit e.g.
64 Mb
e.g.
1FFFF_H 128K
cells
1*(2Mb*32) 1*(2Mb*32)
1FFFF_H 128Kk
cells
e.g.
32 Mb
128 k x 32 bit
32 Mb
0FFFF_H 64K cells 0FFFF_H 64K cells
e.g.
128 Mb
none
256 k x 32 bit e.g.
2*(4Mb*16)
3FFFF_H 256K
cells
0000_H 0
e.g.
64 Mb
none
128 k x 32 bit e.g.
1*(2Mb*32)
1FFFF_H 128K
cells
0000_H 0
e.g.
32 Mb
64 k x 32 bit
none
0FFFF_H 64K cells 0000_H 0
Note: The upstream cell storage RAM must always be connected.
Data Sheet
138
2001-12-17