3. STD Bus Interface
ÛZIATECH
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The ZT 8907 includes a frontplane connector (J6) to support DMA slaves in an STD-80
architecture. J6 provides signals (not defined on the STD-80 bus) that are required by
DMA slaves. See Chapter 6, "
," for an overview of ZT 8907 DMA
architecture and DMA controller operation.
STD 32 BUS COMPATIBILITY
The ZT 8907 is compatible with Version 2.1 of the
STD 32 Bus Specification
. Optional
STD 32 features are discussed in terms of compliance levels.
Permanent Master:
SA16, SA8-I, SDMA8, SDMA16, SDMABP
Temporary Master:
SA16, SA8-{MD}, I, SDMA8, SDMA16, SDMABP
The following topic describes the compliance levels in more detail.
Compliance Levels
The following are brief descriptions of the STD 32 compliance levels supported by the
ZT 8907.
SA8, SA16
Supports 8-bit and 16-bit data transfers with STD-80 signal format
and timings. The ZT 8907 automatically determines the width of the
data transfer at the start of each STD bus operation. STD-80
compatible memory and I/O boards are supported.
I
Supports four additional STD bus interrupts: INTRQ1*, INTRQ2*,
INTRQ3*, and INTRQ4*. These interrupts are input from the
STD bus and connected to the interrupt controller through a
software configurable switch. This feature is selected through the
BIOS SETUP utility. Refer to the "
" table in
Chapter 4 for interrupt routing options.
{MD}
Supports the multiple master (DREQx*, DAKx*) protocol. These two
signals are used by the ZT 8907 in a multiple master architecture to
gain control of STD bus resources. The use of these signals
requires a bus arbiter, such as the ZT 89CT39, to be plugged into
slot X. The ZT 89CT39 must be Revision D or higher.
SDMA8,
SDMA16
Supports 8-bit or 16-bit Standard Architecture DMA as defined in
the STD 32 Bus Specification.
SDMABP
Supports Standard Architecture DMA using BUSRQ*/BUSAK* for
request and acknowledge and the backplane DMA control signals
DMAIOR*, DMAIOW*, and TC.