Hello, one of my customers is experiencing an anomaly when I execute a ‘Clear Faults’ PMBus command (0x03) to TI’s UCD3028 controller (please refer Additional Issue" information below, which descibes the error and bus captured data using an I2C Bus Analyzer as well as the TI’s SMBus/I2C/SAA tool (GUI).
Summary:
Unable to clear fault/warning status bits even though the cause was eliminated (ie., moving limits back outside normal operating regions). Additionally, although the UCD3028 controller does ACK the ‘Clear Faults’ PMBus command (0x03), it NACKs the very next PMBus transaction to it. The UCD3028 controller has the exact same response regardless of whether it’s our GUI or TI’s GUI interface. The problem persists even if the Intermediate Bus power device’s out is disabled.
Are you aware of this problem? If so, do you have a solution, perhaps a UCD3028 controller FW update or different sequence of PMBus commands?
Also, is it possible to receive a list of errata regarding UCD3028 PMBus operations?
Additional Issue information:
Issue:
1. Unable to CLEAR a warning or fault flags.
a. Using the CUI GUI
b. Set OT_WARNING to 0°C in DevCfg tab
c. Device and LSB Fault/Warning LEDs were asserted
d. Reset OT_WARNING to 115°C in DevCfg tab
e. Clicked the ‘Clear Device Faults’ in DevCfg Tab, I2C Bus Capture
Expected Results: [Start]#36[W][A]03[A][Stop]
Unexpected: [Start]#36[W][N][Stop]
Unexpected: [Start]#36[W][N][Stop]
f. While board remained powered, closed the CUI GUI and invoked TI SMBus/I2C/SAA tool.
g. Executed a SendByte with no data to IBC using PMBus command 0x03.
07:18:00.080: SAA #1: SendByte (Address 27d, Cmd 0x03): ACK
h. Initiated a WordRead of IBC’s Status Word using PMBus command 0x79
07:18:40.212: SAA #1: ReadWord (Address 27d, Cmd 0x79): NACK
07:18:54.658: SAA #1: ReadWord (Address 27d, Cmd 0x79): ACK 0x0006
What’s interesting to note is that for some reason, although the TI Controller ACKs the ‘Clear Faults’ command (0x03), the Warning/Fault does NOT get cleared. Moreover, both the TI GUI and the I2C bus analyzer verify the TI Controller’s NACK of the next PMBus command (command type irrelevant). Unable to execute using Ericsson’s GUI because they don’t have a ‘Clear Faults’ option.
Additionally, using the TI SMBus/I2C/SAA tool, I’m able to successfully execute a ‘Clear Faults’ command followed with ACKs for any other immediate PMBus command on a NDM2Z-25H POL.
07:38:01.241: SAA #1: SendByte (Address 4d, Cmd 0x03): ACK
07:38:02.791: SAA #1: SendByte (Address 4d, Cmd 0x03): ACK
07:38:04.192: SAA #1: SendByte (Address 4d, Cmd 0x03): ACK
07:38:04.696: SAA #1: SendByte (Address 4d, Cmd 0x03): ACK
07:38:06.072: SAA #1: ReadWord (Address 4d, Cmd 0x79): ACK 0x0840
07:38:06.745: SAA #1: ReadWord (Address 4d, Cmd 0x79): ACK 0x0840
07:38:07.233: SAA #1: ReadWord (Address 4d, Cmd 0x79): ACK 0x0840
Questions:
- Why is the TI Controller not clearing the Faults and Warnings with the ‘Clear Faults’ PMBus command?
Why is the TI Controller NACKing the very next PMBus transaction?
Hope to receive a detailed response from the UCD3028 TI Apps team.
Thx,
Leo
