Rainbow Electronics W90N740 User Manual

Page 125

W90N740

Publication Release Date: November 26, 2004

- 121 -

Revision A4

NAT Entry x Configuration Registers (NATCFGx)(x: 63 ~ 0)

All NAT Configuration registers, NATCFGx, include enable switches to control IP address and port
number comparison, or replacement. Further, additional inverse (I) bit to control source address (SA)
or destination address (DA) comparison. The NAT function is enabled if either of entry enable bits is
set, else the NAT function is disabled.

For some special applications, the user can reset the port comparison enable bits to ignore port
comparison and do only IP address comparison.

The entry count field, CNTx, is read by S/W to determine when to change either entry data without
miss hit packet processing. If S/W program wants to change some entry data, S/W program has to
disable the selected entry and monitor corresponding CNTx till the value is 0, then it is acceptable to
change new entry data. Otherwise there may be an error condition occurred, for example, when
S/W program has changed entry data, but the previous hit packet is being processed,

and cannot find replacement data.

Register Address R/W

Description

Reset

Value

NATCFG0

NATCFG63

0x7FF06100

0x7FF061FC

R/W

NAT Entry 0 Configuration Register

NAT Entry 63 Configuration Register

0x0000.0000

EHCNTx

Reserved CNTx

Nop Discard

Inverse PxRE AxRE PxCE AxCE ExEN

7.6.2.4 EHCNTx [31:16]: Counter of Packets Hit with Entry x

Default value: 0

The register is read-only, to indicate that how many packets are hit with entry x. When a new packet is
hit with entry x, the corresponding EHCNTx, will increase. The value can be reset to zero by writing
one to corresponding CLREHx in NATCCLR register.