LSI LSI53C1000, Техническое руководство

Страница: 170 / 384

4-60 Registers
Registers: 0x2C–0x2F
DMA SCRIPTS Pointer (DSP)
Read/Write
DSP DMA SCRIPTS Pointer [31:0]
To execute SCSI SCRIPTS, the address of the first
SCRIPTS instruction must be written to this register. In
normal SCRIPTS operation, once the starting address of
the SCRIPT is written to this register, SCRIPTS are
automatically fetched and executed until an interrupt
condition occurs.
In the 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. However, to fetch and execute the next
SCRIPTS command, the Start DMA bit (bit 2,
DMA Con-
trol (DCNTL) register) must be set each time the step
interrupt occurs. When writing this register eight bits at a
time, writing the upper eight bits begins execution of
SCSI SCRIPTS. The default value of this register is zero.
Registers: 0x30–0x33
DMA SCRIPTS Pointer Save (DSPS)
Read/Write
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.
31 0
DSP
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
31 0
DSPS
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0