ISDN and 16-bit Audio
8-13
DBRI Overview
8.2.7
Data structures
DBRI instructions, descriptors and transmit and receive data buffers are
stored in data structures in main memory. Instruction execution is initiated
by loading a pointer to the first instruction into REG8. The DBRI then
continues by fetching instructions from data structures in memory.
All DBRI data structures are aligned on 32-bit boundaries and transmit and
receive descriptor buffers must be aligned on 4-word boundaries.
Figure 8-4 DBRI Data Structures
OP CODE
IIQ
SDP
SDP
WAIT
IQ POINTER
OPTIONS AND PIPE #
TRANSMIT DESCRIPTOR (TD)
POINTER
TRANSMIT DESCRIPTOR (TD)
POINTER
OPTIONS AND PIPE #
FLAGS
CNT
FCNT
TRANSMIT BUFFER ADDRESS (TBA)
NEXT DESCRIPTOR ADDRESS (NDA)
STATUS
TRANSMIT
DATA
BUFFER
IQ EXTEND POINTER
INTERRUPT
QUEUE
SEGMENT (63 WORDS)
RECEIVE BUFFER ADDRESS (TBA)
FLAGS
CNT
STATUS
NEXT DESCRIPTOR ADDRESS (NDA)
BCNT
TRANSMIT BUFFER ADDRESS (TBA)
FLAGS
CNT
STATUS
NEXT DESCRIPTOR ADDRESS (NDA)
BCNT
RECEIVE
DATA
BUFFER
REG8
TRANSMIT
DATA
BUFFER
S3GX_TRMBook Page 13 Friday, September 19, 1997 11:39 am
Summary of Contents for SPARCbook 3 series
Page 8: ...viii S3GX_TRMBook Page viii Friday September 19 1997 11 39 am...
Page 44: ...2 16 The SPARC CPU SBus Controller S3GX_TRMBook Page 16 Friday September 19 1997 11 39 am...
Page 76: ...5 8 SCSI Controller DMA Support S3GX_TRMBook Page 8 Friday September 19 1997 11 39 am...
Page 146: ...9 28 MODEM Class 2 Fax Command Set S3GX_TRMBook Page 28 Friday September 19 1997 11 39 am...
Page 180: ...11 30 Display Interface RAMDAC S3GX_TRMBook Page 30 Friday September 19 1997 11 39 am...
Page 216: ...Index vi S3GX_TRMBook Page vi Friday September 19 1997 11 39 am...