8. Initialization

8.3 Cold Reset Sequence

The Cold Reset sequence is used to reset the entire processor, and possibly alter the mode bits while power and SysClk are stable.

The Cold Reset sequence is as follows:

The external agent negates SysGnt* and SysRespVal*.
After waiting at least one SysClk cycle, the external agent asserts SysReset*.
After waiting at least 100 ms, the external agent loads the mode bits into R10000. This is performed by driving the mode bits on SysAD[63:0], waiting at least two SysClk cycles, and then asserting SysGnt* for at least one SysClk cycle.
After waiting at least another 100 ms for the internal clocks to restabilize, the external agent synchronizes all processor internal clocks by asserting SysRespVal* for one SysClk cycle.
After waiting at least 100 ms for the internal clocks to again restabilize, (a third 100 ms restabilization period) the external agent negates SysReset*.
The external agent must retain mastership of the System interface, refrain from issuing external requests or nonmaskable interrupts, and ignore the system state bus until the processor asserts SysReq*. The assertion of SysReq* indicates the processor is ready for operation. In a cluster arrangement, all processors must assert SysReq*, indicating they are ready for operation.

During a Cold Reset sequence all processor internal state is initialized. A Cold Reset sequence causes the processor to start with a Reset exception.

Figure 8-2 shows the cold reset sequence.

Figure 8-2 Cold Reset Sequence

Copyright 1995, MIPS Technologies, Inc. -- 29 JAN 96

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