LSI 53C810A Computer Hardware User Manual


 
5-39
Register: 0x27 (0xA7)
DMA Command (DCMD)
Read/Write
DCMD DMA Command [7:0]
This 8-bit register determines the instruction for the
LSI53C810A to execute. This register has a different
format for each instruction. For a complete description,
see Chapter 6, “Instruction Set of the I/O Processor.”
Registers:0x28–0x2B (0xA8–0xAB)
DMA Next Address (DNAD)
Read/Write
DNAD DMA Next Address [31:0]
This 32-bit register contains the general purpose address
pointer. At the start of some SCRIPTS operations, its
value is copied from the DMA SCRIPTS Pointer Save
(DSPS) register. Its value may not be valid except in
certain abort conditions. The default value of this register
is zero.
Registers:0x2C–0x2F (0xAC–0xAF)
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
7 0
DCMD
xxxxxxxx
31 0
DNAD
00000000000000000000000000000000
31 0
DSP
00000000000000000000000000000000