DLPC3470 datasheet(27/70 Pages) TI1

27 / 70 page

500 ms (max)

0 ms (min)

(INIT_BUSY)

HOST_IRQ

(with external pullup)

RESETZ

t1 t2

DLPC3470

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DLPS110 – APRIL 2018

Product Folder Links: DLPC3470

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7 Parameter Measurement Information

7.1 HOST_IRQ Usage Model

•

While reset is applied HOST_IRQ will reset to tri-state (an external pullup pulls the line high).

•

HOST_IRQ remains in 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 drives 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 sets HOST_IRQ to a logic low state to indicate the completion

of auto-initialization. (At the falling edge, the system enters the INIT_DONE state.)

•

The 500-ms maximum 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. (see Figure 7)

t1 is the first falling edge of HOST_IRQ, At this point the auto-initiation sequence is complete.

t2 is where HOST_IRQ goes low. Ensure that I2C interface to the device does not begin until this point (within 500 ms

of the release of RESETZ)

Figure 7. Host IRQ Timing

DLPC3470 Datasheet(PDF) 27 Page - Texas Instruments