SK-AM64B: About I2C_probe() processing

Hi Yukinobu,

From the previous mentioned thread, I can see you were able to drive the 3.3 V from User Expansion header. 

Can you please tell the waveform you shared above is captured for which I2C device? As I remember you were able to probe the I2C device earlier.

Yukinobu Hasinoguti said:

Also, the voltage has already risen from 0V to 0.7V before 3.3V is supplied from the user expansion connector.

Which pin of the User expansion connector have you probed?

Regards,

Tushar

Hi Tushar,

Tushar Thakur said:

Can you please tell the waveform you shared above is captured for which I2C device?

This waveform was taken when connecting the SK-AM64B to the MICROCHIP I2C device DT100104.
Unfortunately, I have never been successful in probing this I2C device.

Tushar Thakur said:

Which pin of the User expansion connector have you probed?

I connected it to pins No. 27 (SoC_I2C0_SDA) and No. 28 (SoC_I2C0_SCL) on the user expansion connector.
The voltage did not rise to 0.7V on the MCU Connector's MCU_I2C0_SDA and MCU_I2C0_SCL.

Regards,
Yukinobu

Hi Yukinobu,

I am bit confused here. Can you please confirm what is the use case?

Yukinobu Hasinoguti said:

I connected it to pins No. 27 (SoC_I2C0_SDA) and No. 28 (SoC_I2C0_SCL) on the user expansion connector.
The voltage did not rise to 0.7V on the MCU Connector's MCU_I2C0_SDA and MCU_I2C0_SCL.

Why are you checking the voltage at MCU connector's pin?

Also if the I2C device is connected to SoC_I2C0_SDA & SoC_I2C0_SCL which is main domain I2C instance, why is the MCU_I2C pins are probed?

Have you done the correct configuration in example.syscfg?

Regards,

Tushar

Hi Tushar,

Sorry for the confusion.

Use case 1 is to connect I2C device with SoC_I2C0_SDA,SoC_I2C0_SCL of user extension connector.
Measurement with SoC_I2C0_SDA and SoC_I2C0_SCL shows a rise from 0V to 0.7V.
The oscilloscope waveform is this use case 1 waveform.



Use case 2 is to connect I2C devices to MCU_I2C0_SDA and MCU_I2C0_SCL on the MCU connector.
In use case 2, the voltage did not rise to 0.7V.



The same MICROCHIP I2C device is connected, but the result is different depending on the PIN connected.
SoC_I2C0_SDA,SoC_I2C0_SCL : The voltage goes up to 0.7V
MCU_I2C0_SDA,MCU_I2C0_SCL : Voltage does not rise by 0.7V

Regards,
Yukinobu

Hi Tushar,

Any progress on this 0.7V increase?
Please let me know the status.

Regards,
Yukinobu

Hello Yukinobu,

I have routed your query to Hw expert .

Regards,

Anil.

Hello Yukinobu

Can you please brief the issue?

Yukinobu Hasinoguti said:

Also, the voltage has already risen from 0V to 0.7V before 3.3V is supplied from the user expansion connector.

Is there any signal connected to the IOs on the connector.

Please provide additional details on the connections made.

Regards,

Sreenivasa

Hi Sreenivasa,

A MICROCHIP I2C device (DT100104) is connected to the SK-AM64B user expansion connector with a jumper wire.
When the SK-AM64B is powered on in this state, the voltage rises from 0V to 0.7V.

If the MICROCHIP I2C device (DT100104) is not connected
when the power is turned off and then on, the voltage rises from 0V to 3.3V.

Why does the voltage rise from 0V to 0.7V only when the MICROCHIP I2C device (DT100104) is connected?

SBL NULL has been flashed to the OSPI, so I don't think there are any signals.

Regards,
Yukinobu

Hello Yukinobu

Thank you for the inputs.

Help me understand the microchip attached device connection.

How is the power supply connected to the Microchip device.

Regards,

Sreenivasa

Hi Sreenivasa,

The MICROCHIP device is connected to PIN1 (3V3) of the user expansion connector using a jumper wire.





Power is supplied through the following procedure.

// 3.3V output
I2C_Transaction_init(&i2cTransaction);
i2cTransaction.writeBuf = txBuffer;
i2cTransaction.writeCount = 2;
i2cTransaction.targetAddress = i2cReadTargetAddr;
txBuffer[0] = 0x03;
txBuffer[1] = 0xDF;
status = I2C_transfer(i2c1Handle, &i2cTransaction);

Regards,
Yukinobu

Hello Yukinobu

Thank you.

Can you please make a hand diagram on the connections and share.

the MCU_I2C0 interface has a pullup on the SK board. And the connection is similar to I2C0.

Is there a pull on the add-on board?

Have you checked the software configuration and the connection polarity. 

Regards,

Sreenivasa

Hi Sreenivasa,

Kallikuppa Sreenivasa said:

Can you please make a hand diagram on the connections and share.

Kallikuppa Sreenivasa said:

the MCU_I2C0 interface has a pullup on the SK board. And the connection is similar to I2C0.

Is there a pull on the add-on board?

We are using the I2C0 interface, not the MCU_I2C0 interface, and pull-up resistors are present on the onboard circuit.

Kallikuppa Sreenivasa said:

Have you checked the software configuration and the connection polarity. 

I have confirmed that the SDA and SCL lines are correctly connected between the SK board and the add-on board.
The I2C pull-up resistors are present on the add-on board, and the voltage level is 3.3V, which matches the SK board.
Regarding the software configuration, I have verified that the I2C instance and pinmux settings are correctly set for MCU_I2C0.
The connection polarity is also correct, with SDA and SCL aligned as expected.

Regards,
Yukinobu

Hi,

Just checking in to see if there has been any update on this thread.
I’d appreciate any feedback or guidance.

Regards,
Yukinobu

Hello Yukinobu

Thank you.

Let me check with the team and update.

Regards,

Sreenivasa