PROCESSOR-SDK-J721E: PROCESSOR-SDK-J721E

Deepak Kalalbandi

we are trying to connect to a Slave device (Power over coax) over I2C0. we have initiated read request to the slave through the TI I2C driver API I2C_transfer (). we have observed that communication sequence has started with 7-bit slave address(0x28) being sent on the I2C0 bus and we have also received ACK for the address data, but as soon as the ACK for slave address byte is received, we could see that I2C SCL line pulled low and the communication with the slave device is stopped. Please refer to the attachment from CRO probe on I2C0 bus.

Can you please guide us to debug this issue of SCL line continuously pulled Low.

over 1 year ago

0 Neehar Sawant over 1 year ago

TI__Mastermind 22680 points

Hi,

Thanks for this information. What I2C mode are you operating in?
Thanks,

Neehar

0 Deepak Kalalbandi over 1 year ago in reply to Neehar Sawant

Prodigy 40 points

Hi Neehar,

Thanks for the reply. Below are the settings which we are using for i2c0.

0 Neehar Sawant over 1 year ago in reply to Deepak Kalalbandi

TI__Mastermind 22680 points

Hi Deepak,

Does the issue always occur when reading from the same slave device? Please try to call I2C_recoverBus() and let me know your results.
Thanks,
Neehar

0 Deepak Kalalbandi over 1 year ago in reply to Neehar Sawant

Prodigy 40 points

Hi Neehar,

yes, this issue always occurs when we try to read/write from the slave. we have tried calling the Api I2C_v1_recoverBus () after the read request but we could still see a timeout error. (we have seen that I2C_v1_recoverBus () is called from I2c_Control() API)

0 Neehar Sawant over 1 year ago in reply to Deepak Kalalbandi

TI__Mastermind 22680 points

Hi Deepak,

Can you test the read with I2C_WAIT_FOREVER? Let me know your results.
Thanks,

Neehar

0 Deepak Kalalbandi over 1 year ago in reply to Neehar Sawant

Prodigy 40 points

Hi Neehar,

we have tried with I2C_WAIT_FOREVER without any delay, we did not get any response from I2C_transfer () and I2C SCL line is continuously low.

0 Neehar Sawant over 1 year ago in reply to Deepak Kalalbandi

TI__Mastermind 22680 points

Hi Deepak,

Are you able to read any data before the SCL line is pulled low?
Thanks,

Neehar

0 Deepak Kalalbandi over 1 year ago in reply to Neehar Sawant

Prodigy 40 points

Hi Neehar,

Below is the data which we received before SCL line goes LOW. from the image below we could see that address data(0x28) is received along with ACK and followed by SCL line continuously low.

when we tried with I2C_WAIT_FOREVER without any delay, there is no clock on the SCL line, right from start the SCL line is continuously low and also there is no data being read.

0 Neehar Sawant over 1 year ago in reply to Deepak Kalalbandi

TI__Mastermind 22680 points

Hi Deepak,

Thanks for this information. Can you test if you are able to reset the I2C controller by calling:

I2C_v1_resetCtrl(I2C_Handle handle)

Thanks,

Neehar

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PROCESSOR-SDK-J721E: PROCESSOR-SDK-J721E