Registers: 0x30–0x33

DMA SCRIPTS Pointer Save (DSPS)

Read/Write

31

0

 

DSPS

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

DSPS DMA SCRIPTS Pointer Save[31:0]

This register contains the second Dword of a SCRIPTS instruction. It is overwritten each time a SCRIPTS instruction is fetched. When a SCRIPTS interrupt instruction is executed, this register holds the interrupt vector. The power-up value of this register is indeterminate.

Registers: 0x34–0x37

Scratch Register A (SCRATCHA)

Read/Write

31

0

 

SCRATCHA

x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x

SCRATCHA Scratch Register A

[31:0]

This is a general purpose, user-definable scratch pad register. Apart from CPU access, only Register Read/Write and Memory Moves into the SCRATCH register alter its contents. The power-up value of this register is indeterminate.

A special mode of this register is enabled by setting the PCI Configuration Into Enable bit in the Chip Test Two (CTEST2) register. If this bit is set, the SCRATCH A register returns bits [31:10] of the Memory Mapped Operating register PCI base address (Base Address Reg- ister One (MEMORY)) in bits [31:10] of the Scratch Reg- ister A (SCRATCHA) when read. Bits [9:0] of SCRATCH A will always return zero in this mode. Writes to the SCRATCH A register are unaffected. Clearing the PCI Configuration Into Enable bit causes the SCRATCH A register to return to normal operation.

SCSI Registers

4-65

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LSI 53C875A DMA Scripts Pointer Save Dsps Read/Write, Dsps DMA Scripts Pointer Save310, Scratcha Scratch Register a 310