SCSI Functional Description
2-21
DACs can be generated for all SCRIPTS operations. There are six
selector registers which hold the upper Dword of a 64-bit address. All but
one of these is static and requires manual loading using a CPU access,
a Load and Store instruction, or a memory move instruction. One of the
selector registers is dynamic and is used during 64-bit direct block moves
only. All selectors will default to zero, meaning the LSI53C1000 will
power-up in a state where only Single Address Cycles (SACs) are
generated. When any of the selector registers are written to a nonzero
value, DACs are generated.
Direct, Table Indirect and Indirect Block Moves, Memory-to-Memory
Moves, Load/Stores, and Jumps are all instructions with 64-bit address
capability.
Note:
Crossing the 4 Gbyte boundary on any one SCRIPTS
operation is not permitted. Therefore, software must handle
all such transactions.
2.2.4 Hardware Control of SCSI Activity LED
The LSI53C1000 controls an LED through the GPIO_0 pin to indicate
that it is connected to the SCSI bus. This function was previously
handled by a software driver.
Bit 3 (CON), in the
Interrupt Status Zero (ISTAT0)
register, is presented
at the GPIO_0 pin when the following occurs:
•
Bit 5 (LED_CNTL) in the
General Purpose Pin Control (GPCNTL)
register is set,
•
Bit 6 (Fetch Enable) in the
General Purpose Pin Control (GPCNTL)
register is cleared,
•
the LSI53C1000 is not performing an EEPROM autodownload.
The CON (Connected) bit in
Interrupt Status Zero (ISTAT0)
is set anytime
the LSI53C1000 is connected to the SCSI bus either as an initiator or a
target. This happens after the LSI53C1000 has successfully completed
a selection or when it has successfully responded to a selection or
reselection. The CON bit is also set when the LSI53C1000 wins
arbitration in low level 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...
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Страница 360: ...A 8 Register Summary...
Страница 376: ...IX 12 Index...