the first SCRIPTS instruction is written to this register, SCRIPTS instructions are automatically fetched and executed until an interrupt condition occurs.

In single step mode, there is a single step interrupt after each instruction is executed. The DMA SCRIPTS Pointer (DSP) register does not need to be written with the next address, but the Start DMA bit (bit 2, DMA Control (DCNTL) register) must be set each time the step interrupt occurs to fetch and execute the next SCRIPTS command. When writing this register eight bits at a time, writing the upper eight bits begins execution of the SCSI SCRIPTS. The default value of this register is zero.

Registers: 0x30–0x33 (0xB0–0xB3)

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.

5-40

Operating Registers

Page 114
Image 114
LSI 53C810A Registers 0x30-0x33 0xB0-0xB3, DMA Scripts Pointer Save Dsps Read/Write, DMA Scripts Pointer Save 310