Motorola MC68030 User Manual page 272

8-4
The MC68030 provides the STATUS signal to identify instruction boundaries
and some exceptions. As shown in Table 8-2, STATUS indicates an instruction
boundary and exceptions to be processed, depending on the state of the
internal microsequencer. In addition, STATUS indicates when an MMU ad-
dress translation cache miss has occurred and the processor is about to begin
a table search access for the logical address that caused the miss. Instruction-
related exceptions do not cause the assertion of STATUS as shown in Table
8-1. For STATUS signal timing information, refer to SECTION 12 APPLICA-
TIONS INFORMATION.
Table 8-2. Microsequencer STATUS Indications
Asserted for Indicates
1 Clock Sequencer at instruction boundary will begin execution of next instruction.
2 Clocks Sequencer at instruction boundary but will not begin the next instruction im-
mediately due to:
• pending trace exception
OR
• pending interrupt exception
3 Clocks MMU address translation cache miss - processor to begin table serach
OR
Exception processing to begin for:
• reset OR
• bus error OR
• address error OR
• spurious interrupt OR
• autovectored interrupt OR
• F-line instruction (no coprocessor responded)
Continuously Processor halted due to double bus fault.
MC68030 USER'S MANUAL MOTOROLA