ZCOM Tables and Data Structures

Interface Table

This is a 16-bit field refreshed by the DAM once every 10 seconds with the runtime information word from the Mux firmware. It contains the average percentage activity of the Mux interface for the previous 10 seconds and the type code of the Mux front panel connected.

IFBOFF - Buffer pointer adjusted offset

Contained with the interface table are buffers that are used for DMA transfers between the driver and the Mux card. These buffers are a multiple of 64 bytes and must be aligned on a 64-byte address boundary. This field contains the byte offset needed to cause the buffers to start on a 64-byte boundary. TTGEN initializes this field with the byte offset value.

INTFCQ - Interface control queue (zqhd_type)

This queue contains pending port requests from application programs. The operation of this queue is described in the section on the DAM. This format of the queue header structure (zqhd_type) is described later in this chapter.

IFDMAQ - DMA receive buffer queue (zqhd_type)

Holds the current receive buffer during an $RXDT DMA transfer. This format of the queue header structure (zqhd_type) is described later in this chapter.

TXCX_HEAD - Pointer to head of the express queue linked lists

TXCA_HEAD - Pointer to head of the high-priority queue linked lists

TXCB_HEAD - Pointer to head of the low-priority queue linked lists

ITXLSTX - Pointer to express terminal list array (in union)

ITXLSTA - Pointer to high-priority terminal list array (in union)

ITXLSTB - Pointer to low-priority terminal list array (in union)

IPLIMIT - Pointer to port/subchannel unack Tx limit array (in union)

IPBYTES - Pointer to port/subchannel unack Tx size array (in union)

IPSTAT - Pointer to port/subchannel status array (in union)

IPCNTR - Pointer to # of terminals per port/subchannel array (in union) IPORTN - Pointer to port configuration array (in union)

IFPLOOK - Pointer to PTT interrupt vector array.

IFCMDBP - Pointer to current backplane command buffer (in union)

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Chapter 3