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8-8
ISDN and 16-bit Audio
DBRI Overview
REG0: Status and
Control Register
Bit
15
P – This bit is set by the host or by the DBRI when REG8
(command pointer) is written. It is cleared by the DBRI
when a WAIT command is encountered on the command
list. When the bit is set, the DBRI begins executing
commands from system memory, starting at the location
pointed by the value in REG8.
Bit 14
G – This bit is used to enable 4-word burst transfers. This bit
is cleared when a 4-word burst fails on the SBus. This bit is
set by a hardware or software reset.
Bit 13
S – This bit is used to enable 16-word burst transfers. It is
cleared when a 16-word burst fails on the SBus and cleared
by a hardware or software reset.
Bit 12
E – This used to enable 8-word burst transfers. This bit is
cleared when an 8-word burst fails on the SBus. This bit is
cleared by a hardware or software reset.
Bit 7
X – This bit is set and cleared by the host. If this bit is set,
the sanity timer is reset and disabled (TO pin held high).
Clearing this bit restarts the sanity timer.
Bit 6
T – Permit Activation of the TE Interface. This bit is set and
cleared by the host.
Bit 5
N – Permit Activation of the NT Interface. This bit is set and
cleared by the host.
Bit 4
C – Permit Activation of the CHI Interface. This bit is set
and cleared by the host.
Bit 3
F – This bit is set and cleared by the host. Setting this bit
forces an immediate time-out of the sanity timer (overrides
X bit). With the F bit set, the TO pin is low and remains low
until this bit is cleared. This bit is set by a hardware or
software reset. Unless the F bit is cleared, the sanity timer
remains in the time-out state (TO remains low) even when
registers are accessed.
Bit 2
D – This bit is set and cleared by the host. Setting this bit
immediately disables any activity initiated by the DBRI.
Since DMA is disabled, the DBRI stalls, and if left set long
enough, the D8RI could have overrun and underrun
conditions.
S3GX_TRMBook Page 8 Friday, September 19, 1997 11:39 am
Содержание SPARCbook 3 series
Страница 1: ...Series Technical Reference Manual 980327 02 3 S3GX_TRMBook Page i Friday September 19 1997 11 39 am...
Страница 8: ...viii S3GX_TRMBook Page viii Friday September 19 1997 11 39 am...
Страница 28: ...1 16 Architecture Overview Microcontroller Subsystem S3GX_TRMBook Page 16 Friday September 19 1997 11 39 am...
Страница 44: ...2 16 The SPARC CPU SBus Controller S3GX_TRMBook Page 16 Friday September 19 1997 11 39 am...
Страница 76: ...5 8 SCSI Controller DMA Support S3GX_TRMBook Page 8 Friday September 19 1997 11 39 am...
Страница 82: ...6 6 Ethernet Interface DMA Support for Network Operations S3GX_TRMBook Page 6 Friday September 19 1997 11 39 am...
Страница 96: ...7 14 PCMCIA Interface Microcontroller Registers S3GX_TRMBook Page 14 Friday September 19 1997 11 39 am...
Страница 146: ...9 28 MODEM Class 2 Fax Command Set S3GX_TRMBook Page 28 Friday September 19 1997 11 39 am...
Страница 180: ...11 30 Display Interface RAMDAC S3GX_TRMBook Page 30 Friday September 19 1997 11 39 am...
Страница 210: ...B 10 Connector Information Removable Hard Drive SCSI Connector S3GX_TRMBook Page 10 Friday September 19 1997 11 39 am...
Страница 216: ...Index vi S3GX_TRMBook Page vi Friday September 19 1997 11 39 am...