UCD90320: What is the structure of the UCD90320 Device ID protocol?

David Cananzi

Part Number: UCD90320

To whom it may concern,

We use a UCD90320 device and we would like to use the GUI. However, we find that when the GUI sends the scan using the device ID protocol (MFR_SPECIFIC_45, command address 0xDF) it conflicts with some other devices. Do you know how this command works? What is the transaction sequence?

Thank you,
David

over 2 years ago

0 yihe over 2 years ago

TI__Guru 66340 points

You meant 0xFD instead of 0xDF.

If you have other devices on the same I2C bus which also support the 0xFD command, you can let the GUI to skip those device's address to avoid the conflict.

Regards

Yihe

0 David Cananzi over 2 years ago

Prodigy 120 points

Hi Yihe,

I see that, but we are trying to make an I2C bridge. So we need to know how the 0xFD transaction is structured.

This document gives the PMBus Command Guide

UCD90320 Sequencer and System Health Controller PMBus Command Reference (Rev. C) (ti.com), I am looking at Section 10.43, for the readback of 32 bytes.

It looks like the command is:

<Start>

SlaveAddress<Wn>

<ACKn>

<ACKn>

<Start>

SlaveAddress<R>

<ACKn>

<ACKn>

......

<NACK, master>

<Stop>

Question:

Does the UCD90320 use the reserved I2C device ID command 0xFD? (see I²C - Wikipedia, Reserved addresses in 7-bit address space)

Does what is the specific I2C command sequence for this PMBus command?

0 yihe over 2 years ago in reply to David Cananzi

TI__Guru 66340 points

Sorry for the late response, I was OOO for one week.

I am not sure what your question is.

0xFD is a read-block command please refer SMBus spec.

Regards

Yihe

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UCD90320: What is the structure of the UCD90320 Device ID protocol?