AX88875AP Bripeater

ASIX ELECTRONICS CORPORATION

10

Note 1 :

The calculation formulas of Traffic Utilization between ASIX and NetCom is difference, so you will

get different results when using SmartBit (SB) testing this item.

We found the SmartBit calculate the Utilization without include 96 Bit time inter frame gap. So the

utilization value can be 100%. As well as we found SB used min packet size (64 byte) and min IFG (96

bit-time) as 100% utilization. In theory, when max packet size(1518 byte) and min IFG the utilization

will be more than 100%, but SB also treat it as 100%.

In our AX88875 design, we use real cable bandwidth as calculation base. We calculate the bit counts of

carrier within a unit time. Because of the existence of inter frame gap, In our calculation 100%

utilization is impossible. So the above two cases (64 byte packet size and 1518 byte packet size with

min. IFG ), we will count as 85.7% and 99.2%.

If using SB test result to indicate utilization LED the value must be modified. See the following

reference table.

ASIX’s Utilization%

1

5

10

15

30

60

SmartBit’s Utilization%

2

7

12

17

34

68

2.3 Buffer memory pins group

Signal Name

Type Pin No.

Description

BMA[16:0]

O

88-82,

80, 79,

107-104,

102-99

Buffer address bus.

BMD[7:0]

I/O

97-90

Buffer data bus.

/BMWR

I/O

78

Memory control pin for write.

/BMA[15]

I/O

73

Invert Buffer address 15.

Utilization % /LUTI0 /LUTI1 /LUTI2 /LUTI3 /LUTI4 /LUTI5

0

1

1

1

1

1

1

1

0

1

1

1

1

1

5

0

0

1

1

1

1

10

0

0

0

1

1

1

15

0

0

0

0

1

1

30

0

0

0

0

0

1

60

0

0

0

0

0

0