TI380C25 Datasheet, PDF (10/71 Pages) Texas Instruments – TOKEN-RING COMMPROCESSOR

TI380C25
TOKEN-RING COMMPROCESSOR
SPWS012 – JANUARY 1995
PIN
NAME
NO.
SHLDA / SBGR ⁵⁸
SHRQ / SBRQ
78
SIACK
43
I/O^†
I
O
I
Pin Functions (Continued)
DESCRIPTION
Intel Mode
SHLDA is used for system-hold acknowledge. SHLDA indicates that the system DMA
hold request has been acknowledged. It is internally synchronized to SBCLK
(see Note 1).
H = Hold request acknowledged
L = Hold request not acknowledged
Motorola
Mode
SBGR is used for system bus grant. SBGR is an active-low bus grant, as defined in the
standard 68xxx interface, and is internally synchronized to SBCLK (see Note 1).
H = System bus not granted
L = System bus granted
Intel Mode
SHRQ is used for system-hold request. SHRQ is used to request control of the system
bus in preparation for a DMA transfer. SHRQ is internally synchronized to SBCLK.
H = System bus requested
L = System bus not requested
Motorola
Mode
SBRQ is used for system-bus request. SBRQ is used to request control of the system
bus in preparation for a DMA transfer. SBRQ is internally synchronized to SBCLK.
H = System bus not requested
L = System bus requested
System-interrupt acknowledge. SIACK is from the host processor to acknowledge the interrupt request
from the TI380C25.
H = System interrupt not acknowledged (see Note 1)
L = System interrupt acknowledged: The TI380C25 places its interrupt vector onto the system
bus.
System Intel / Motorola mode select. The value on SI / M specifies the system-interface mode.
SI / M
56
I
H = Intel-compatible interface mode selected. Intel interface can be 8-bit or 16-bit mode
(see S8 / SHALT description and Note 1).
L = Motorola-compatible interface mode selected. Motorola interface mode is always 16 bits.
SINTR / SIRQ
57
SINTR is used for system-interrupt request. TI380C25 activates SINTR to signal an
interrupt request to the host processor.
Intel Mode
H = Interrupt request by TI380C25
L = No interrupt request
O
SIRQ is used for system-interrupt request. TI380C25 activates SIRQ to signal an
Motorola ^{interrupt request to the host processor.}
Mode _{H = No interrupt request}
L = Interrupt request by TI380C25
SOWN
System bus owned. SOWN indicates to external devices that TI380C25 has control of the system bus.
SOWN drives the enable signal of the bus-transceiver chips that drive the address and bus-control
81
O
signals.
H = TI380C25 does not have control of the system bus.
L = TI380C25 has control of the system bus.
† _{I = input, O = output}
NOTE 1: Pin has an internal pullup device to maintain a high-voltage level when left unconnected (no etch).
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