Use the PWM value of MCU and DPsource in common

[yamakatb]

I am currently checking the device operation of PTN3460I.

I want to adjust the brightness of both the I2C master and the DP source.
To do this, both settings must be the same.

Question.
Is it possible to get the rewritten PWM Value via DPCD registers (0x722 & 0x723) in the Configuration Register (0x90 & 0x91)?

After the reset is released, you can read the DefaultValue by reading the Configuration Registers (0x90 & 0x91) and DPCD registers (0x722 & 0x723).

When I rewrote the Configuration Registers (0x90 & 0x91) with I2C-bus master, I was able to confirm the change in brightness.
You can also read the rewritten PWM Value with Configuration Registers (0x90 & 0x91).

The PWM Value rewritten by I2C-bus master could also be read by DPCD registers (0x722 & 0x723).

Next, when I rewrote the DPCD registers (0x722 & 0x723) again with I2C-Over-Aux, I was able to confirm the change in brightness.
You can read the rewritten PWM Value with DPCD registers (0x722 & 0x723),
In the Configuration Register (0x90 & 0x91), the PWM Value rewritten in the previous Configuration Register (0x90 & 0x91) could be read.

[guoweisun]

You can use the DPCD tool to read then write these registers.

[yamakatb]

Hi @guoweisun 

Do "these registers" refer to both DPCD registers and Configuration Registers?

Where can I get the DPCD tool?

Best regards,
yamakatb

[guoweisun]

You can use the DPCD tool to write then read this registers.

[guoweisun]

Q:

Is it possible to get the rewritten PWM Value via DPCD registers (0x722 & 0x723) in the Configuration Register (0x90 & 0x91)?

A:Yes,I think it's.

[yamakatb · Accepted solution]

Hi @guoweisun 
Thank you for your reply

The PWM value rewritten using DPCD registers cannot be read from the Configuration Register, and the PWM value rewritten using the Configuration Register last time can be read.

Is it necessary to somehow update the Configuration Register after accessing it from the DPCD registers?

Since the operation of DPCD registers access and Configuration Register has been confirmed independently, I think that there is no problem with the access method, but is there any other possible cause for the register value not changing?

Best regards,
yamakatb