RT 1062 EVB LCD connection problem

[EthanKu]

We are confused that Why LCD interface (LCDIF_D0~ D11) needs pull-down resistor and LCDIF_D12~D15 doesn’t at EVB. if LCD is used to our project

[kerryzhou]

Hi @EthanKu ,

   Thank you for your interest in the NXP MIMXRT product, I would like to provide service for you.

  In fact, it is not directly determined by the LCD, it is determined by the BOOT_CFG pin, as the BOOT_CFG pin is multiplexed with the LCD pin.

The following information from the HWDG document will help you understand it:

Wish it helps you!
Best Regards,

Kerry

[EthanKu]

HI Kerry 

thank you for supporting 

I still have some questions about the description as below

using LCD boot interface lines as inputs may result in a wrong boot 

1. So it should be set as output?
2. What is the meaning of LC boot?

[kerryzhou]

Hi @EthanKu ,

   Thanks for your updated information.

   Answer your questions:

using LCD boot interface lines as inputs may result in a wrong boot 

1. So it should be set as output?

=>Answer: During boot, the BOOT_CFG is input pin in default.

After you configure it to the LCD pins in the code, then it is the output pin.

But, still need to note, when reset, or POR, during boot, the LCD pin will back to the input status for the BOOT_CFG function before you enter the app code.

So, what you need to do is make sure during the boot, the external circuit will input the correct status for the BOOT_CFG, it is not for the LCD.

2. What is the meaning of LC boot?

=>My understanding is the LCD boot, not LC boot, should the typo.

It means, the BOOT_CFG pin also used as LCD pin, but add the external pull circuit situation for the BOOT_CFG pins.

Anyway, you need to make sure the BOOT_CFG pin during boot as input situation, the input status should cause the correct BOOT.

To the LCD signal, I think the EVK BOOT related pull circuit won't influence the LCD output display.

So, in fact, you do the external pull circuit for the BOOT function, not the LCD function.

Best Regards,

Kerry 

[EthanKu]

Hi Kerry 

thank you kindly supporting 

i got it 

[kerryzhou · Accepted solution]

Hi @EthanKu ,

    You are welcome!

    If your question is solved, please help to mark the correct answer, just to close this case, any new issues, welcome to create the new question post, thanks.

Best Regards,

kerry