PXF4336 Datasheet, PDF (214/425 Pages) Infineon Technologies AG – ABM Premium ATM Buf fer Manager

7.2.5
ABM-P
PXF 4336 V1.1
Register Description
Buffer Threshold and Occupation Capture Registers
Register 16 UBufMax/DBufMax
Upstream/Downstream Buffer Maximum Threshold Registers
CPU Accessibility:
Reset Value:
Offset Address:
Typical Usage:
Read/Write
0000_H
UBufMax 24_H
Written by CPU
DBufMax 25_H
Bit
15
14
13
12
11
10
9
8
UBufMax/DBufMax(17:10)
Bit
7
6
5
4
3
2
1
0
UBufMax/DBufMax(9:2)
UBufMax(17:2)
DBufMax(17:2)
Upstream Buffer Maximum Threshold
Downstream Buffer Maximum Threshold
These bit fields determine a maximum limit for the total upstream
and downstream buffer size with a granularity of 4 cells. The values
depend on:
• The size of the external cell pointer RAM,
• Whether the downstream cell storage RAM is connected.
See Table 7-3 for recommended values.
The CPU programs the maximum number of cells with a granularity
of 4 by right shifting the value by 2:
xBufMax(17:2):= (maximum_cells(17:0) >> 2)
Table 7-3 provides typical values and related RAM sizes:
Data Sheet
214
2001-12-17