This way the SCRIPTS can move on to the next instruction before the reselection completes. It continues executing SCRIPTS until a SCRIPT that requires a response from the Initiator is encountered.

If the LSI53C875A is selected or reselected before winning arbitration, it fetches the next instruction from the address pointed to by the 32-bit jump address field stored in the DMA Next Address (DNAD) register. Manually set the LSI53C875A to Initiator mode if it is reselected, or to Target mode if it is selected.

Disconnect Instruction

The LSI53C875A disconnects from the SCSI bus by deasserting all SCSI signal outputs.

Wait Select Instruction

If the LSI53C875A is selected, it fetches the next instruction from the address pointed to by the DMA SCRIPTS Pointer (DSP) register.

If reselected, the LSI53C875A fetches the next instruction from the address pointed to by the 32-bit jump address field stored in the DMA Next Address (DNAD) register.

Manually set the LSI53C875A to Initiator mode when it is reselected.

If the CPU sets the SIGP bit in the Interrupt Status Zero (ISTAT0) register, the LSI53C875A aborts the Wait Select instruction and fetches the next instruction from the address pointed to by the 32-bit jump address field stored in the DMA Next Address (DNAD) register.

Set Instruction

When the SACK/ or SATN/ bits are set, the corresponding bits in the SCSI Output Control Latch (SOCL) register are set. Do not set SACK/ or SATN/ except for testing purposes. When the target bit is set, the corresponding bit in the SCSI Control Zero (SCNTL0) register is also set. When the carry bit is set, the corresponding bit in the Arithmetic Logic Unit (ALU) is set.

Note: None of the signals are set on the SCSI bus in Target mode.

Clear Instruction

I/O Instruction

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LSI 53C875A technical manual Disconnect Instruction, Wait Select Instruction, Set Instruction, Clear Instruction