TI380C27 Datasheet, PDF (25/77 Pages) Texas Instruments – DUAL-PROTOCOL COMMPROCESSOR

TI380C27
DUAL-PROTOCOL COMMPROCESSOR
SIF adapter-control register (SIFACL) (continued)
SPWS014A – APRIL 1994 – REVISED MARCH 1995
Bit 11:
LBP – Local-Bus Priority
This bit controls the priority levels of devices on the local bus.
0 = No external devices (such as the TI380FPA) are used with the TI380C27.
1 = An external device (such as the TI380FPA) is used with the TI380C27. This allows the
external bus master to operate at the necessary priorities on the local bus.
If the system uses the TMS380SRA only, the bit must be set to 0. If the system uses both the
TMS380SRA and the TI380FPA, this bit must be set to 1.
Bit 12:
SINTEN — System-Interrupt Enable
This bit allows the host processor to enable or disable system-interrupt requests from the
TI380C27. The system-interrupt request from the TI380C27 is on SINTR/SIRQ. The following
equation shows how SINTR/SIRQ is driven. The table also explains the results of the states.
SINTR/SIRQ = (PSDMAEN * SWHRQ * !SWHLDA) + (SINTEN * SYSTEM_INTERRUPT)
PSDMAEN SWHRQ SWHLDA SINTEN
1†
1
1
X
1†
1
0
X
1†
0
0
X
X
X
X
1
0
X
X
1
0
X
X
0
† _{The value on SHLDA / SBGR is ignored.}
SYSTEM
INTERRUPT
(SIFSTS
REGISTER)
X
X
X
1
0
X
RESULT
Pseudo DMA is active.
The TI380C27 generated a system interrupt for a pseudo DMA.
Not a pseudo-DMA interrupt.
The TI380C27 generates a system interrupt.
The TI380C27 does not generate a system interrupt.
The TI380C27 cannot generate a system interrupt.
Bit 13:
PEN — Parity Enable
This bit determines whether data transfers within the TI380C27 are checked for parity.
0 = Data transfers are not checked for parity.
1 = Data transfers are checked for correct odd parity.
Bit 14 – 15:
NSELOUT0, NSELOUT0 1 — Network-Selection Outputs
The values in these bits control NSELOUT0 and NSELOUT1. These bits can be modified only
while the ARESET bit is set.
These bits can be used to software configure a multiprotocol TI380C27 as follows: NSELOUT0
and NSELOUT1 should be connected to TEST0 and TEST1, respectively (TEST2 should be left
unconnected or tied high). NSELOUT0 is used to select network speed and NSELOUT1 is used
to select network type as shown in the table below:
NSELOUT0
0
0
1
1
NSELOUT1
0
1
0
1
SELECTION
Full-duplex Ethernet
16-Mbps token ring
Half-duplex Ethernet
4-Mbps token ring
At power up, these bits are set corresponding to 16-Mbps token ring (NSELOUT1 = 1,
NSELOUT0 = 0).
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