TDA4VM: Can GPIO pins be intended to use as MDIO clock and MDIO data line

Manisha Narayana Gowda

Part Number: TDA4VM
Other Parts Discussed in Thread: DRA829J

Tool/software:

Hello all,
We have a requirement to use GPIO pins as MDIO clock and data line pins. Is it possible to communicate with the PHY by using the GPIO pins where the work around of errata I2329 will be implemented. Is it possible to read and write to PHY register GPIO pins. Is it possible for the PHY to recognize the frame fields? As of now I configured data line as Input and output, MDIO clock pin as output.

If yes, how initialization of GPIO to be done while for MDIO, we need to configure MDIO in manual mode (Acc. to i2329 work around ) (Configuring the MANUALMODE).

Kind Regards
Thank You
Manisha Narayana Gowda

11 months ago

0 Doredla Sudheer Kumar 11 months ago

TI__Guru 63470 points

Hi,

You can use GPIO Pins for MDIO transactions, but it is not recommended as we have dedicated MDIO Pins.

Best Regards,
Sudheer

0 Manisha Narayana Gowda 11 months ago in reply to Doredla Sudheer Kumar

Intellectual 280 points

Manisha Narayana Gowda said:
If yes, how initialization of GPIO to be done while for MDIO, we need to configure MDIO in manual mode (Acc. to i2329 work around ) (Configuring the MANUALMODE).

Can you please answer this?

0 Doredla Sudheer Kumar 11 months ago in reply to Manisha Narayana Gowda

TI__Guru 63470 points

Hi,

Manisha Narayana Gowda said:
Manisha Narayana Gowda said:
If yes, how initialization of GPIO to be done while for MDIO, we need to configure MDIO in manual mode (Acc. to i2329 work around ) (Configuring the MANUALMODE).

Can you please answer this?

Please refer to GPIO usage examples from PDK (pdk/packages/ti/drv/gpio/test/led_blink/src/main_led_blink.c).
As mentioned above, it is not recommended to use GPIOs for MDIO whereas MDIO pins are available.

Possible issues will be traces of GPIOs used for MDIO may not be same length which lead wrong pattern detection at MDIO slave side.

Best Regards,
Sudheer

0 Manisha Narayana Gowda 11 months ago in reply to Doredla Sudheer Kumar

Intellectual 280 points

Hello Sudheer,
I am referring to ball number : AA27 and Y26 (PADCONFIG84 and PADCONFIG845) to use as GPIO pins because I could not find the registers for PRG0_MDIO0_MDIO and PRG0_MDIO0_MDIC.
I could find only two MDIO registers CPSW0_MDIO and MCU_CPSW0_MDIO Registers, If GPIO pins are not recommended to use as MDC and MDIO pins, where can I find the registers for PRG0_MDIO0_MDIO and PRG0_MDIO0_MDIC.

Kind Regards
Thank You
Manisha N G

0 Doredla Sudheer Kumar 11 months ago in reply to Manisha Narayana Gowda

TI__Guru 63470 points

Hi,

Manisha Narayana Gowda said:
where can I find the registers for PRG0_MDIO0_MDIO and PRG0_MDIO0_MDIC.

These are PRU core MDIO Pins. Not CPSW MDIO Pins. PRU core it self not enabled in TI SDK.

Best Regards,
Sudheer

0 Manisha Narayana Gowda 11 months ago in reply to Doredla Sudheer Kumar

Intellectual 280 points

Hi,
How to enable it. How can I make use of these pins as MDIO. So again it is the same question, Where can I find the registers for these MDIO?

Thank you
Manisha N G

0 Doredla Sudheer Kumar 11 months ago in reply to Manisha Narayana Gowda

TI__Guru 63470 points

Hi,

Manisha Narayana Gowda said:
How to enable it. How can I make use of these pins as MDIO. So again it is the same question, Where can I find the registers for these MDIO?

As mentioned above, you can't use those Pins as those are tied up with PRU0ICCSG core for MDIO functionality similar to CPSW MDIO Pins.

You can configure those pins in GPIO Mode and implement MDIO protocol on it.

Doredla Sudheer Kumar said:
Please refer to GPIO usage examples from PDK (pdk/packages/ti/drv/gpio/test/led_blink/src/main_led_blink.c).

As pointed above for reference code of GPIO, please refer to PDK example.

Best Regards,
Sudheer

0 Dmitry Tuykov 10 months ago in reply to Doredla Sudheer Kumar

Expert 1221 points

Hello Sudheer,

may I extend the questions of my colleague:

- Mentioned above PRU core, does it exist for DRA829J?

- Is there any limitation / difference between using 'native' MDIO (e.g. from CSPW 2G system) pins by switching MDIO in manual mode and using mentioned above PRU MDIO pins in simple GPIO mode?

Thanks,
Dmitry

0 Doredla Sudheer Kumar 10 months ago in reply to Dmitry Tuykov

TI__Guru 63470 points

Hi,

Dmitry Tuykov said:
- Mentioned above PRU core, does it exist for DRA829J?

Yes, but no s/w support from TI SDK.

Dmitry Tuykov said:
- Is there any limitation / difference between using 'native' MDIO (e.g. from CSPW 2G system) pins by switching MDIO in manual mode and using mentioned above PRU MDIO pins in simple GPIO mode?

As per our understanding, there won't be any performance change.

But, might need to care of signal routing and pull up's.

If MDIO and MDC signals trace length vary may cause fault mdio transactions.

So, we recommend to use MDIO pins itself in manual mode. As there are dedicated for mdio operations.

Also, refer to above updates for more clarity and understanding.

Best Regards,

Sudheer

0 Dmitry Tuykov 10 months ago in reply to Doredla Sudheer Kumar

Expert 1221 points

Hi Sudheer,

Doredla Sudheer Kumar said:
Yes, but no s/w support from TI SDK

Is it disable by default? We need to avoid having any unused components 'running' and therefore interfere the system.

Doredla Sudheer Kumar said:
As per our understanding, there won't be any performance change.

But, might need to care of signal routing and pull up's.

Thank you, this is enough the the moment.

Thanks,
Dmitry

0 Doredla Sudheer Kumar 10 months ago in reply to Dmitry Tuykov

TI__Guru 63470 points

Hi,

Dmitry Tuykov said:
Doredla Sudheer Kumar said:
Yes, but no s/w support from TI SDK

Is it disable by default? We need to avoid having any unused components 'running' and therefore interfere the system.

Yes, its disabled by default. so, you can use as ICSS MDIO pins, can be used as GPIOs.

Best Regards,
Sudheer

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TDA4VM: Can GPIO pins be intended to use as MDIO clock and MDIO data line