MAC Control/Status

Setting this bit resets the port: promiscuous mode is disabled, multicast is disabled, any supplied multiple individual addresses are lost. All of the internal memory structures for the port are reinitialized, and the port is reinitialized with power on default values.

Enable/Disable MAC (EM)

With SM set, setting this bit enables the MAC for both transmits and receives. If this bit is not set, the port will not transmit, nor will it receive. Without SM, the bit reports status.

Abort Pending (AP)

Causes any pending receives for this port to be aborted.

Abort Report (AR)

With this bit set, any pending receives aborted with the AP bit or by setting the Initialize MAC bit will be returned to the host with the appropriate error code set.

Set Individual address (IA)

With SM set, this bit changes the individual address for the port. The new station address needs to be located by the Buffer Address field defined above. Without SM, the current station address for the port will be returned. Please refer to the Buffer Address field definition for details on how to locate this in Short I/O.

Enable Promiscuous mode (PM)

With SM set, enables promiscuous reception on the port. Otherwise returns status.

Enable multi-cast receptions (MC)

With SM set enables native multi-cast receptions. On the Intel 596, this corresponds to Multi-Cast All, in which all multicast frames are returned to the host. Use the multicast setup options specific to the 596 defined below to set up particular filters. Otherwise reports current status.

Enable loopback (LPB)

With SM set places port in the native loopback mode. With the 596, this corresponds to External Loopback. Additional modes are provided by the 596-specific functions below. Otherwise reports loopback status of port.

Perform TDR test (TDR)

If SM bit is set, causes a TDR test to be executed on the port, and returns the number of 10 MHz ticks which elapsed between the beginning of the test and the collision which ended it. Otherwise returns the results for the last test executed, or zero.

Intel 82596 Status/Control – Transmit Functions

This field provides direct host access to several functions provided by the Intel 82596 Ethernet control chip controlling the transmit function. Users of these functions should be aware that they are quite specific to the Intel 82596, and should code accordingly. Users who desire portability should use the generic MAC control functions provided above.

These functions are fully documented in the Intel documentation. They are not intended to be used without referring to that source.

Note: The specific source document referred to here is the Intel 32 Bit Local Area Network (LAN) Component User’s Manual, 1992 (Order No. 296853-001). Use of an alternate Intel document for reference may have the necessary information but may not correspond to the page numbers listed below.

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