LMH0397: Port numbering for device tree in Petalinux

Tamar Mosiashvili

Part Number: LMH0397

Hi all,
I am using LMH0397 for SDI IO interface. From the block diagram I can't figure out what are the port numbering, I need to set it as an input or output.

Where can I find programming guide for this? I figured out this is how to set ports as i/o but I also do not know what reg numbers are

port@0 {
 reg = <0>;
 };
 port@1 {
 reg = <1>;
 };
 port@2 {
 reg = <2>;
 };
 port@3 {
 reg = <2>;
 };

over 2 years ago

0 Drew Miller1 over 2 years ago

TI__Mastermind 36933 points

Hi,

You can request access to the programming guide using the link below.

https://www.ti.com/drr/opn/LMH0397-DESIGN

Thanks,

Drew

0 Tamar Mosiashvili over 2 years ago in reply to Drew Miller1

Prodigy 10 points

I have this document, but it says nothing about device tree or port numbering

0 Drew Miller1 over 2 years ago in reply to Tamar Mosiashvili

TI__Mastermind 36933 points

Hi Tamar,

I'm not sure that I understand your question, can you clarify?

The ports used in the programming guide match with the ports in the datasheet. For example, "OUT0" in the programming guide matches with "OUT0", pins 22/23 in the datasheet.

Thanks,

Drew

0 Tamar Mosiashvili over 2 years ago in reply to Drew Miller1

Prodigy 10 points

I am trying to include it in the device tree for petalinux and Im not sure how to program it either input or output. Is there Linux driver or example device tree for this part? As far as Im discerned I cant access the ports with "OUT0" name in the device tree

Thank you

Tamar

0 Drew Miller1 over 2 years ago in reply to Tamar Mosiashvili

TI__Mastermind 36933 points

Hi Tamar,

There is not a linux driver for this device. We can help advise on what SPI/I2C writes are required to achieve a certain outcome, but we don't have experience integrating this device into linux.

Thanks,
Drew

0 Tamar Mosiashvili over 2 years ago in reply to Drew Miller1

Prodigy 10 points

Please do so, any info is much appreciated!

I am using I2C bus to set 3 lmh0397, 1 as input and 2 as output. How can I achieve this?

Thank you

Tamar

0 Drew Miller1 over 2 years ago in reply to Tamar Mosiashvili

TI__Mastermind 36933 points

Hi Tamar,

Can you clarify which inputs and outputs are used on the LMH0397 in your system?

I would strongly recommend looking at section 3.1 of the programming guide. This provides examples as to how different inputs and outputs can be selected.

Thanks,
Drew

0 Tamar Mosiashvili over 2 years ago in reply to Drew Miller1

Prodigy 10 points

Whats not so clear is which mode from 3.1.21 and 3.1.2 tables is for input and which is for output, do we need EQ mode when its set as input and CD mode when its output?

Are the tables showing a set of i2c write transactions like

i2c_write(device_address,FF,00,07) //Select Share Register Page

i2c_write(device_address,FE,02,02) //Override EQ/CD_SEL pin setting with value in Reg 0xFE[0]

i2c_write(device_address,FE,00,01) //Select SDI_IO as input (EQ Mode)

.....

This is how we connect the lmh0397 in out schematics

Thank you for your support

Tamar

+1 Drew Miller1 over 2 years ago in reply to Tamar Mosiashvili

TI__Mastermind 36933 points

Hi Tamar,

I think it's important for us to clarify what you mean by input and output so that we can verify if EQ or CD mode should be selected. Please reference Table 3 (below) from the datasheet and identify which input/output configurations you are using. This will help us understand if EQ mode or CD mode should be selected.

Looking at your schematic, it seems like you are using the configurations I've highlighted below depending on if the LMH0397 is configured as "input" or "output". Can you confirm if my understanding is correct?

Based on this, are you able to modify the common configurations suggested in 3.1.1 and 3.1.2 to select the appropriate inputs and outputs?

Thanks,

Drew

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LMH0397: Port numbering for device tree in Petalinux