PXF4333 Datasheet, PDF (174/361 Pages) Infineon Technologies AG – ABM 3G ATM Buf fer Manager

7.2.4 Buffer Occupation Counter Registers
ABM-3G
PXF 4333 V1.1
Register Description
Register 14 UBufferOcc/DBufferOcc
Upstream/Downstream Buffer Occupation Registers
CPU Accessibility:
Reset Value:
Offset Address:
Typical Usage:
Read only
0000_H
UBufferOcc 20_H
Read by CPU
DBufferOcc 21_H
Bit
15
14
13
12
11
10
9
8
UBufferOcc/DBufferOcc(17:10)
Bit
7
6
5
4
3
2
1
0
UBufferOcc/DBufferOcc(9:2)
UBufferOcc(17:2)
DBufferOcc(17:2)
Upstream Buffer Occupation Counter
Downstream Buffer Occupation Counter
These bit fields represent the most significant 16 bits of the internal
18-bit wide counters reflecting the number of cells currently stored
in the upstream/downstream cell storage RAM.
The CPU determines the buffer fill level with a granularity of 4 by
reading register UBufferOcc/DBufferOcc and left shifting the value
by 2:
fill_level(17:0):= (xBufferOcc(17:2) << 2)
Data Sheet
174
2001-12-17