Forum Post: TMS320F280025: Handling CLK_LOW_TIMEOUT in PMBus Communication with Unresponsive Master

Part Number: TMS320F280025 Tool/software: Dear expert, I am asking for customer. They’ve encountered an issue with our F280025 PMBus module holding the SCL line low for about 35ms without receiving a NACK , which triggers a CLK_LOW_TIMEOUT . However, when the CLK_LOW_TIMEOUT is triggered, it doesn’t enter the PMBUS_STACK_ASSERT(0) block as expected. This diagram shows the issue they encountered. Their master device didn’t send a NACK, which caused the MCU to enter an uncontrolled state. As you can see, the C2000 should have completed the transaction after responding with data 0x01 , but instead, it got stuck. Here are some questions and observations: Is there a standard handling mechanism for CLK_LOW_TIMEOUT in TI's PMBus stack? They’ve checked the sample code, but would like to confirm what exactly PMBusStack_errorHandler() handles internally . As a workaround, They added a check for CLK_LOW_TIMEOUT at the beginning of each pmbus_stack_handler_target() function. If the timeout flag is set, it triggers PMBus_errorHandler() for reinitialization. Is this workaround valid and recommended? Additionally: What’s the difference between "PMBus over I2C" and regular PMBus usage in terms of behavior and compatibility? Since the MCU is using the dedicated PMBus module, is it still possible to receive and process standard I2C messages correctly ? Best Regards, Eric Chen