TMS320F280048C-Q1: I2C not able to generate stop condition

Hi Hang,

I will get back to you on this tomorrow.

Best Regards,

Aishwarya

Hang,

Have you referred to the I2C EEPROM examples in C2000WARE as they showcase how to interface with and send various # of bytes to an EEPROM?

Please refer to these resources as well:

Interfacing EEPROM Using PMBus in I2C Mode

(+) I2C master doesn't generate STP condition (TMS320F28335) - C2000 microcontrollers forum - C2000︎ microcontrollers - TI E2E support forums

Best Regards,

Aishwarya

Hi Ashwarya,

Customer built their I2C communication on top of the ex2 EEPROM example, their code are mostly the same as the writedata() function in the example.

I checked the referenced link. In that post, seems STP is not generated because there bytes remaining FIFO. However, My customer is using repeat mode, the i2ccnt is don't care

More importantly, if this is a configuration issue, it should happens every time. However, it only happens by chance, about 20%, In the rest of the time, it works normally.

Regards,

Hang.

Hang,

Let me get back to you by the end of the week on this matter.

Best Regards,

Aishwarya

Hang,

If there is only one controller on the bus, then most probably the target is holding the bus low due to incorrect software configuration or hang in the target code.

What is the I2C controller clock and baud rate configured to, and does this match the EEPROM being used?

What are the pull up resistors being used on the SDA / SCL lines? These are necessary to transition the bus from low to high state and vice versa.

Best Regards,

Aishwarya

Hi Aishwarya,

I'd like to add one background here. The I2C interface works fine all the time when the slave is "asked" to send 2 or more bytes of data. Considering this, I think the baud rate and pull-up resistor should be OK.

If it's the target that holds the bus low incorrectly, is there any way to identify this by looking at the waveforms?

Regards,

Hang

Hang,

Hang Yang said:

I'd like to add one background here. The I2C interface works fine all the time when the slave is "asked" to send 2 or more bytes of data. Considering this, I think the baud rate and pull-up resistor should be OK.

Are there other devices sharing the bus and is it possible to share more details regarding the code and/or the EEPROM being used? It sounds like the EEPROM may require 2 bytes of data to be sent at a time which is why the I2C communication always works correctly. More information here on I2C EEPROM comms: Interfacing EEPROM Using PMBus in I2C Mode

Best Regards,

Aishwarya

Hi Aishwarya,

I shared the EEPROM part internally. There is only this EEPROM on the bus, no other devices. 

Regards,

Hang.

Thanks, Hang. Have asked a question via chat. I will be out of the office until the week 01/06/2025, so I will get back to you then. Happy Holidays!

Best Regards,

Aishwarya

Hi Hang,

Have you been able to resolve this query? If there are no more questions, I will go ahead and close this thread.

Best Regards,

Aishwarya

Hi Aishwarya,

I just had feedback form customer that the root cause has not been found yet, lets keep on finding the root cause.

Regards,

Hang. 

Hang,

Let me know if you were able to get the answer in our offline chat. Could you reshare the datasheet of the EEPROM as well as I cannot see our chat anymore for some reason.

Best Regards,

Aishwarya