UCD9244 POR startup and External Reset

fdm

Expert 1070 points

Hi,

There's an internal startup sequence that UCD9244 initiates at power-up, and its duration is 10ms to 125ms.

Does this sequence affected by an External Reset signal applied to the nRESET pin?

BR, Denis

over 8 years ago

0 Zhiyuan Hu over 8 years ago

TI__Genius 9845 points

Power cycling the device and toggling the nRESET pin both will trigger the initialization sequence. The sequence starts when nRESET pin is released.

0 fdm over 8 years ago in reply to Zhiyuan Hu

Expert 1070 points

How could the end of that startup sequence be detected by an external host? How does the PMBus behave during startup?

0 Zhiyuan Hu over 8 years ago in reply to fdm

TI__Genius 9845 points

No PMBus communication during initialization.

If the rails are set to "Always converting", PWM will start once initialization is finished.

If the rails are set to "CONTROL pin", and CONTROL is asserted, PWM will start once initialization is finished.

If the rails are set to "OPERATION", host will get NACK if it sends an OPERATION or any other command before initialization is finished.

Power management

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UCD9244 POR startup and External Reset