80960CA-33 Datasheet, PDF (14/68 Pages) Intel Corporation – 80960CA-33, -25, -16 32-BIT HIGH-PERFORMANCE EMBEDDED PROCESSOR

80960CA-33, -25, -16
Table 5. 80960CA Pin Description — DMA and Interrupt Unit Control Signals
Name
DREQ3:0
DACK3:0
EOP/TC3:0
XINT7:0
NMI
Type
I
A(L)
H(Z)
R(Z)
O
S
H(1)
R(1)
I/O
A(L)
H(Z/Q)
R(Z)
I
A(E/L)
H(Z)
R(Z)
I
A(E)
H(Z)
R(Z)
Description
DMA REQUEST causes a DMA transfer to be requested. Each of the four signals
requests a transfer on a single channel. DREQ0 requests channel 0, DREQ1
requests channel 1, etc. When two or more channels are requested simulta-
neously, the channel with the highest priority is serviced first. The channel priority
mode is programmable.
DMA ACKNOWLEDGE indicates that a DMA transfer is being executed. Each of
the four signals acknowledges a transfer for a single channel. DACK0 acknowl-
edges channel 0, DACK1 acknowledges channel 1, etc. DACK3:0 are asserted
when the requesting device of a DMA is accessed.
END OF PROCESS/TERMINAL COUNT can be programmed as either an input
(EOP3:0) or as an output (TC3:0), but not both. Each pin is individually program-
mable. When programmed as an input, EOPx causes the termination of a current
DMA transfer for the channel corresponding to the EOPx pin. EOP0 corresponds
to channel 0, EOP1 corresponds to channel 1, etc. When a channel is configured
for source and destination chaining, the EOP pin for that channel causes
termination of only the current buffer transferred and causes the next buffer to be
transferred. EOP3:0 are asynchronous inputs.
When programmed as an output, the channel’s TCx pin indicates that the channel
byte count has reached 0 and a DMA has terminated. TCx is driven with the same
timing as DACKx during the last DMA transfer for a buffer. If the last bus request is
executed as multiple bus accesses, TCx will stay asserted for the entire bus
request.
EXTERNAL INTERRUPT PINS cause interrupts to be requested. These pins can
be configured in three modes:
Dedicated Mode:
each pin is a dedicated external interrupt source. Dedicated
inputs can be individually programmed to be level (low) or
edge (falling) activated.
Expanded Mode:
the eight pins act together as an 8-bit vectored interrupt
source. The interrupt pins in this mode are level activat-
ed.Since the interrupt pins are active low, the vector number
requested is the one’s complement of the positive logic
value place on the port. This eliminates glue logic to
interface to combinational priority encoders which output
negative logic.
Mixed Mode:
XINT7:5 are dedicated sources and XINT4:0 act as the five
most significant bits of an expanded mode vector. The least
significant bits are set to 010 internally.
NON-MASKABLE INTERRUPT causes a non-maskable interrupt event to occur.
NMI is the highest priority interrupt recognized. NMI is an edge (falling) activated
source.
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