adm6999ux Infineon Technologies Corporation, adm6999ux Datasheet - Page 51

• Manufacturer Part Number: adm6999ux
• Description: Adm6999u 9 Port 10/100 Mb/s Single Chip Ethernet Switch Controller
• Manufacturer: Infineon Technologies Corporation

Port Buffer Threshold Control Register P4, P5
PBTCR_P45
Port Buffer Threshold Control Reg. P4, P5
Field
Port_5
Port_4
Port Buffer Threshold Control Register P6, P7
PBTCR_P67
Port Buffer Threshold Control Reg. P6, P7
Field
Port_7
Port_6
ADM6999U/UX supports buffer management scheme with dynamic thresholds to ensure the fair share of memory
among different port queues. If users need each port to have a fixed threshold, they can configure the Bit 14 in the
27
Dynamic threshold management:
Bit[7]: The add bit. Bit[6:0]: The offset bits.
When Bit[7] = 1, the switch will use the value (buffers really used + 2*bit[6:0]) as the buffer count that the port has
used.
When Bit[7] = 0, the switch will use the value (buffers really used - 2*bit[6:0]) as the buffer count that the port has
used.
Fixed threshold management:
Bit[3:0]: The buffer threshold bits.
When the total buffer was not reached, the buffer amount allocated to each port will be equal to bit[3:0] * 4.
Data Sheet
H
to 1.
Bits
15:8
7:0
Bits
15:8
7:0
Type
rw
rw
Type
rw
rw
Description
Port5, Odd Port Buffer Threshold Control
Port4, Even Port Buffer Threshold Control
Description
Port7, Odd Port Buffer Threshold Control
Port6, Even Port Buffer Threshold Control
Offset
Offset
25
26
51
H
H
Rev. 1.42, 2005-11-25
ADM6999U/UX
Data Sheet
Descriptions
Reset Value
Reset Value
0000
0000
H
H