While reset is applied HOST_IRQ will reset to tri-state (an external pullup pulls the line high).
HOST_IRQ will remain tri-state (pulled high externally) until the microprocessor boot completes. While the signal is pulled high, this indicates that the ASIC is performing boot-up and auto-initialization.
As soon as possible after boot-up, the microprocessor will drive HOST_IRQ to a logic high state to indicate that the ASIC is continuing to perform auto-initialization (no real state change occurs on the external signal)
Upon completion of auto-initialization, software will set HOST_IRQ to a logic low state to indicate the completion of auto-initialization. (At the falling edge, the system is said to enter the INIT_DONE state.)
The 500-ms maximum shown from the rising edge of RESETZ to the falling edge of HOST_IRQ may become longer than 500 ms if many commands are added to the autoinit batch file in flash which automatically runs at power up.