SK-AM64B: How do I supply power from the user expansion connector?

Yukinobu Hasinoguti

Part Number: SK-AM64B
Other Parts Discussed in Thread: SYSCONFIG, TCA6424, TCA9538,

Tool/software:

Hi,

I'm expecting 3.3V to be supplied from pin 1 of the user expansion connector,
but when I checked with an oscilloscope, I found that no power was being supplied.
Similarly, no power is being supplied to pin 17.
Is there any setting I need to make to supply power from the user expansion connector?

Regards,
Yukinobu

6 months ago

0 Kallikuppa Sreenivasa 6 months ago

TI__Guru**** 189679 points

Hello Yukinobu

Thank you for the query.

The load switch is disabled.

Regards,

Sreenivasa

0 Yukinobu Hasinoguti 6 months ago in reply to Kallikuppa Sreenivasa

Intellectual 300 points

Hi Sreenivasa,

Kallikuppa Sreenivasa said:
The load switch is disabled.

How do I enable the load switch? Do I change the SYSCONFIG settings?
I don't understand how to enable the load switch.
Can you provide specific steps to enable the load switch?

Regards,
Yukinobu

0 Kallikuppa Sreenivasa 6 months ago in reply to Yukinobu Hasinoguti

TI__Guru**** 189679 points

Hello Yukinobu

Thank you.

Yukinobu Hasinoguti said:
The load switch is disabled.

How do I enable the load switch? Do I change the SYSCONFIG settings?
I don't understand how to enable the load switch.
Can you provide specific steps to enable the load switch?

Sure. Let me check internally and assign to a software expert to support.

Regards,

Sreenivasa

0 Yukinobu Hasinoguti 6 months ago in reply to Kallikuppa Sreenivasa

Intellectual 300 points

Hi Sreenivasa,

I used this FAQ as a reference.
I think it's a very good FAQ.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1326205/faq-processor-sdk-am64x-how-to-program-tca6424a-using-soc_i2c1?tisearch=e2e-sitesearch&keymatch=TCA6424

The version I'm using is mcu_plus_sdk_am64x_10_01_00_32.
This version has the TCA6424 drivers, but not the SK-AM64B's TCA9538 drivers.
I thought I could use the second method in the FAQ to supply 3.3V power to the user expansion connector. Is that correct?

(Q1)
What should I set here to supply 3.3V power to the SK-AM64B's user expansion connector?

(Q2)
Is the value I should set the TCA9538 address (0x70)?

(Q3)
If you have an example of programming the SK-AM64B's TCA9538 similar to this FAQ, please provide it.

Regards,
Yukinobu

0 Kallikuppa Sreenivasa 5 months ago in reply to Yukinobu Hasinoguti

TI__Guru**** 189679 points

Hello Yukinobu

Thank you.

I will have to check internally who could support and reassign.

This is going to take some time.

Regards,

Sreenivasa

0 Tushar Thakur 5 months ago in reply to Yukinobu Hasinoguti

TI__Mastermind 48758 points

Hi Yukinobu,

Yukinobu Hasinoguti said:
(Q1)
What should I set here to supply 3.3V power to the SK-AM64B's user expansion connector?

Which port you want to configure as output? You can follow the same steps suggested in the above FAQ.

Send the command to I2C device to configure the direction of ports to output by writting 0 to corresponding bit in configuration register.

Please refer below code.

buffer[0] = 0x03;
buffer[1] = 0xFB; // to set P2 as output

Yukinobu Hasinoguti said:
(Q2)
Is the value I should set the TCA9538 address (0x70)?

From the I2C device datasheet, I can see it can be configured to 4 different addresses. Make sure you are using the correct target address. Valid addresses are 0x70, 0x71, 0x72, 0x73.

Please refer below image.

Yukinobu Hasinoguti said:
(Q3)
If you have an example of programming the SK-AM64B's TCA9538 similar to this FAQ, please provide it.

We don't have an example for the above mentioned I2C part.

Hope the above information helps.

Regards,

Tushar

0 Yukinobu Hasinoguti 5 months ago in reply to Tushar Thakur

Intellectual 300 points

Hi Tushar,

I'm sorry but could you please help me solve this problem?

When I read the IO expander (0x70), it was 0x8F (1000 1111).

So I added a process to set P5 to 1, but it was unable to supply 3.3V to the user expansion connector.

I also set P4 and P5, but it was unable to supply 3.3V either.

Is there anything else I need to fix?

I2C_Transaction_init(&i2cTransaction);
i2cTransaction.writeBuf   = txBuffer;
i2cTransaction.writeCount = 2;
i2cTransaction.targetAddress = i2cReadTargetAddr;
txBuffer[0] = 0x03;
txBuffer[1] = rxBuffer[0]|0x30;
status = I2C_transfer(i2cHandle, &i2cTransaction);

Regards,

Yukinobu

0 Tushar Thakur 5 months ago in reply to Yukinobu Hasinoguti

TI__Mastermind 48758 points

Hi Yukinobu,

Please find the below image which shows the pin functions of TCA9583 IC.

Here when the device is powered up, all the ports(P0-P7) are configured as input.

You can configure the pin/port direction to output by writing 0 to respective bit of configuration register. Please refer below image.

Now which pin you want to control, just write 0 to the corresponding bit. For e.g. if I want to control P4 as output, the value needs to be written is 0xEF.

Hope the above clarifies.

Regards,

Tushar

0 Yukinobu Hasinoguti 5 months ago in reply to Tushar Thakur

Intellectual 300 points

Hi Tushar ,

I modified the example i2c_temperature_am64x-sk_r5fss0-0_nortos_ti-arm-clang and read the TCA9583 IC after powering it on, but the value was 0x8F.

The value is different from the default value when powered on.

Q1)

I call I2C_probe() before reading, is that the cause?

Q2)

If I don't call I2C_probe(), the read will fail with I2C_transfer() and an error will occur.

How can I read the correct TCA9583 IC value?

Regards,
Yukinobu

0 Tushar Thakur 5 months ago in reply to Yukinobu Hasinoguti

TI__Mastermind 48758 points

Hi Yukinobu,

Are you trying to read the input port registers? This registers can have random values.

Please refer below image.

Regards,

Tushar

0 Yukinobu Hasinoguti 5 months ago in reply to Tushar Thakur

Intellectual 300 points

Hi Tushar,

My understanding was wrong.
I was able to confirm with an oscilloscope that the voltage at P1 on the user expansion connector increased.
Thank you so much for all your support.

Regards,
Yukinobu

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SK-AM64B: How do I supply power from the user expansion connector?