MSPM0L1306: I2C target clock stretch

Hello 

I am so sorry that I am sick today. And I will check and reply to you tomorrow.

Thank you, take care

Hi, zhuang

I am here to help Janz and you.

zhuang tian said:

when MSPM0L1306 powered on with sda or scl pulled down

How do you configure the SDA and SCL Pin? Just follow the demo code and didn't modify GPIO configuration?

zhuang tian said:

then disconnect with gnd,

According to your schematic, SDA and SCL should return to High after disconnecting with GND, right?

zhuang tian said:

How to explain this situation,  what happen to i2c module?

For I2C Target(Slave), it requires pullup resistor to keep High during Idle and Init. Manually pulldown these two lines is abnormal. 

You can enter debug mode and after going through all this issue reproduce step, have a look at I2C, GPIO or IOMUX status register. Find any abnormal status flags.

Such as GPIO's status and I2C target clock stretch related register: TREQ and RREQ, and etc.

Regards,

Helic

Hi Helic,

Thanks for your reply.

I understand manually pulldown scl or sda is abnormal, but it is the test i need to simulate scl or sda accidently pulled down. 

I test the code provided by sdk example

\ti\mspm0_sdk_1_20_01_06\examples\nortos\LP_MSPM0L1306\driverlib\i2c_target_rw_multibyte_fifo_interrupts

I  comment the  __WFI()  

I reproduced the test.

when power on, SCL and SDA is high          ---> normal

when I connect GND to SCL, it goes low     --->  normal, in debug mode no interrupt triggered, no status changed.

when disconnect GND, SCL still keep low   --->  can't understand, why it can't recover to high. which means master can't control this line anymore.

Hi, 

I will do some test in TI lab.

Regards,

Helic

Hi, 

I have test the demo: 

here is the result:

I didn't see what you said.

And I saw an addtional positive pulse while powering on.

Which version launchPad and L1306 are you using? Maybe a sample chip? not a RTM version.

Regards,

Helic

Hi Helic,

How to check the LaunchPad version and L1306 version. Which one is RTM version.

I tested two LanuchPads I had, they all showed the same result I described.  

Hi, zhuang

Please check the bottom view of LaunchPad, and the mark on MSPM0L1306.

Regards,

Helic