Use STM32MP157 with 4 lanes DSI display

[MBESS.21]

Hi,

I'm working with the STM32MP157 and I'm trying to interface it with 4 lanes DSI display.

the problem is that the STM32MP157 support only DSI with 2 lanes. In the other hand, I can't program the controller of the display (JD9365DA-H3) to switch with 2 lanes display.

So I want to know if the display can work with only 2 lanes instead of 4.

In general, how we can interface (no programmable) 4 lanes display with STM32MP157

Thank you

[Tesla DeLorean]

Isn't there a command channel via the first lane?​

[MBESS.21]

Hi Tesla DeLorean,

The display driver is materially set in 4 lanes DSI mode (by connecting the concerning pin to Vcc or Vdd), So I can't change it.

[Tesla DeLorean]

The two lanes of the STM32 ultimately constrain the frequency and bandwidth of the display.

If the ​screen doesn't adapt then it is likely not usable.

[Erwan SZYMANSKI]

Hello @MBESS.2​ ,

Confirming @Community member​ comment.

The MP157 is providing only 2 data lanes, that is a fact and we will not be able to workaround at the board level.

Now you need to take a look at the specifications of your panel. It is highly possible that this last one support different data lanes number configurations (maybe from 2 to 4 etc..). If this is the case, you will have to check how to configure it to pass on 2 data lanes from the panel point of view. I not, no way to use it with MP157.

Last thing to consider, the connection between the chip and the panel may be limited in frequency. You will have to check which is the maximum freq that you can put on DSI lanes, and make your configuration depending on that.

Kind regards,

Erwan.