Chapter 3 - MACSI Host Interface

Abort Report (AR)

Setting this bit causes commands aborted with either the AA or the AN bit to be reported back to the host with the appropriate error code set. Setting this bit has no effect on pending receives for particular ports aborted via the Abort Pending bit in the MAC Status/Control field.

Setting all three of these bits (AA, AN, AR) will cause all pending receives posted for all ports, plus all non- designated pending receives to be returned to the host with the appropriate error set.

Return Status

Full error return status details will be available after the module level design is complete.

Buffer address

This field contains the address of the 6-byte Individual Address when the command is used to set the station address, or a list of possible addresses when setting up Multiple Individual Address or Multicast Address filtering. Otherwise the contents of this field are ignored. With the correct Memory Type specified in the DMA Control Word (bit 9 = 0, bit 8 = 0), this value could be an offset into Short I/O. The contents of the memory location specified in this way will be reserved for the controllers use, and not available to the host, until the IOPB is returned. Writing additional information into this field while the controller is processing the IOPB may cause undefined behavior.

Transfer size

This field contains the size in bytes of the data to be transferred from the location specified above.

MAC status/control

This field provides a general set of MAC level functions, which drivers can use to control the particular port without any reference to the actual Ethernet control chip used on the controller. Drivers using these functions will be portable to other Interphase Ethernet controllers employing this same MACSI host interface, though they may use different front end chips. Programs, such as diagnostics and specialized network monitoring programs, can use the following two fields to obtain direct access to more specialized functions provided by the particular Ethernet control chips employed.

Table 3-24. MAC Status / Control

MAC Status/Control

Offst

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0x0B

 

 

 

 

 

 

 

TDR

LPB

MC

PM

IA

AR

AP

EM

IM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Initialize MAC (IM)

Setting this bit (along with the SM bit in the Command Options word) resets the port. This sets all management counters for the port to zero, resets the physical interface circuitry, and aborts any pending receives. Without the Enable MAC bit set, neither transmits nor receives will be active, and the port will respond only to control commands issued through the Control MAC IOPB.

80