2-20
Functional Description
fetches remain internal to the chip and do not use the PCI bus. In
addition, any SCRIPTS instruction that contains a source or destination
address residing in SCRIPTS RAM memory space remains internal to
the chip and does not generate PCI cycles. SCRIPTS instructions able
to access SCRIPTS RAM memory space in this manner include
Memory-to-Memory Moves, Load/Stores, and Block Moves. While an
internal cycle is occurring, any external PCI slave cycle is retried on the
PCI bus. Setting the DISRC (Disable Internal SCRIPTS RAM Cycles) bit
in the
register disables this feature.
SCRIPTS RAM should be initialized before it is read. Reading SCRIPTS
RAM before initialization sets the SCRIPTS RAM parity bit, bit 7, in the
register.
PCI system BIOS can relocate the RAM anywhere in the 64-bit address
space.
Base Address Register Three (BAR3) (SCRIPTS RAM)
and
Address Register Four (BAR4) (SCRIPTS RAM)
, in the PCI configuration
space, contain the base address of the internal RAM. To simplify
SCRIPTS instruction loading, the base address of the RAM appears in
the
register when bit 3 of the
register is set. The upper 32 bits of a 64-bit base address
are in the
register. The RAM is
byte-accessible from the PCI bus and is visible to any bus mastering
device on the bus. External, CPU accesses to the RAM follow the same
timing sequence as a standard slave register access, except that the
required target wait states drop from 5 to 3. SCRIPTS RAM must first be
written before being read in order to initialize SCRIPTS RAM parity. If a
SCRIPTS RAM parity error is encountered, a SCSI Gross Error interrupt
will be signaled.
A complete set of development tools is available for writing custom
drivers with SCSI SCRIPTS. For more information on the SCSI SCRIPTS
instructions supported by the LSI53C1000, see
2.2.3 64-Bit Addressing in SCRIPTS
The PCI interface for the LSI53C1000 provides 64-bit address and data
capability in the initiator mode. The chip can also respond to 64-bit
addressing in the target mode.
Содержание LSI53C1000
Страница 6: ...vi Preface...
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Страница 28: ...1 12 Introduction...
Страница 234: ...4 124 Registers...
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Страница 350: ...6 76 Specifications Figure 6 42 LSI53C1000 329 Ball Grid Array Bottom view...
Страница 352: ...6 78 Specifications...
Страница 360: ...A 8 Register Summary...
Страница 376: ...IX 12 Index...