TI380C30 Datasheet, PDF (26/78 Pages) Texas Instruments – INTEGRATED TOKEN-RING COMMPROCESSOR AND PHYSICAL-LAYER INTERFACE

TI380C30
INTEGRATED TOKEN-RING
COMMPROCESSOR AND PHYSICAL-LAYER INTERFACE
SPWS016A – NOVEMBER 1994 – REVISED JULY 1995
SIF adapter-control register (SIFACL) (continued)
Bit 11:
LBP — Local-Bus Priority
Controls the priority levels of devices on the local bus.
0 = No external devices (such as TI380FPA) are used with the TI380C30.
1 = An external device (such as TI380FPA) is used with the TI380C30. This allows the external
bus master to operate at the necessary priority 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, the bit must be set to 1.
Bit 12:
SINTEN — System-Interrupt Enable
Allows the host processor to enable or disable system-interrupt requests from the TI380C30.
The system-interrupt request from the TI380C30 is on SINTR / SIRQ. The following equation
shows how SINTR / SIRQ is driven. The table details 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 TI380C30 generated a system interrupt for a pseudo DMA.
Not a pseudo-DMA interrupt
The TI380C30 generates a system interrupt.
The TI380C30 does not generate a system interrupt.
The TI380C30 cannot generate a system interrupt.
Bit 13:
PEN — Parity Enable
Determines whether data transfers within the TI380C30 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
Values 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 TI380C30: NSELOUT0 should be connected to
TEST0 (TEST1 should be left unconnected and TEST2 should be tied high). NSELOUT0 and
NSELOUT1 are used to select network speed as shown in the table below:
NSELOUT0
0
0
1
1
NSELOUT1
0
1
0
1
SELECTION
Reserved
16-Mbps token ring
Reserved
4-Mbps token ring
At power up, these bits are set corresponding to 16-Mbps token ring (NSELOUT1 = 1,
NSELOUT0 = 0).
26
• POST OFFICE BOX 1443 HOUSTON, TEXAS 77251–1443