WRIE Write and Invalidate Enable0

This bit, when set, causes issuing of Memory Write and

Invalidate commands on the PCI bus whenever legal.

These conditions are described in more detail in

Chapter 3, “PCI Functional Description.”

Registers: 0x1C–0x1F (0x9C–0x9F)

Temporary (TEMP)

Read/Write

31

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TEMP

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TEMP

 

 

Temporary

[31:0]

 

 

 

 

 

 

 

 

 

 

 

 

This 32-bit register stores the Return instruction address

 

 

 

 

 

 

 

 

 

 

 

 

pointer from the Call instruction. The address pointer

 

 

 

 

 

 

 

 

 

 

 

 

stored in this register is loaded into the DMA SCRIPTS

 

 

 

 

 

 

 

 

 

 

 

 

Pointer (DSP) register when a Return instruction is

 

 

 

 

 

 

 

 

 

 

 

 

executed. This address points to the next instruction to

 

 

 

 

 

 

 

 

 

 

 

 

execute. Do not write to this register while the

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LSI53C810A is executing SCRIPTS.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

During any Memory-to-Memory Move operation, the

 

 

 

 

 

 

 

 

 

 

 

 

contents of this register are preserved. The power-up

 

 

 

 

 

 

 

 

 

 

 

 

value of this register is indeterminate.

 

 

 

Register:

0x20 (0xA0)

 

 

 

 

 

 

 

DMA FIFO (DFIFO)

 

 

 

 

 

 

 

Read/Write

 

 

 

 

 

 

 

 

 

 

 

7

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

R

 

 

 

 

 

 

 

BO[6:0]

 

 

 

 

x

 

0

 

0

 

0

 

0

0

0

 

0

R

 

Reserved

 

 

 

 

 

 

7

BO[6:0]

 

Byte Offset Counter

 

 

 

 

[6:0]

 

 

 

These bits indicate the amount of data transferred

 

 

 

 

between the SCSI core and the DMA core. It may be

 

 

 

used to determine the number of bytes in the DMA FIFO

5-33

Page 107
Image 107
LSI 53C810A technical manual Registers 0x1C-0x1F 0x9C-0x9F, Register 0x20 0xA0, Temp, DMA Fifo Dfifo