Issues about I.MX280 LCD_RS Pin

[tony_l_cai]

Hi, all

     In our i.mx280 custom board, we will use LCD ,and at the same time,we will boot from LCD pins(boot mode set by LCD pins). So, firstly, I want to know what the function of LCD_RS pin is in LCD module.

    Then, we want to know whether it will make some  effect when we both use the LCD and boot mode? and how to handle with the LCD_RS pin? Because if I need to boot from  LCD pin, I should pull up the LCD_RS,but if I pull up the pin, then how to change the LCD_RS signal in LCD module?

    Please give me some advice. 3Q!

[igorpadykov · Accepted solution]

Hi tony

please refer to attached i.MX28 EVK schematic p.15.

One can pull LCD lines with 10K resistors as shows schematic,

they will not hamper i.MX28 LCD signals.

Best regards

igor

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[tony_l_cai]

Hi igor

    could you tell me what is the function of the LCD_RS in LCD module?

    and this pin has pulled up in evk sch, and is fixed. But There is a  function of the LCD_RS in LCD module,which is "The LCD_WR signal is used as the write strobe while

LCD_RS signal is typically used to switch between command and data modes."(P2454 in MCIMX28RM.pdf), so In my mind,LCD_RS needs to change the its signal in LCD module, doesn't it ? But in evk sch, the LCD_RS is pulled up( is fixed), and cannot switch its signal. What I think is right? if not, please give me some explanation or advice about how to use the LCD_RS pin in boot mode and LCD module at the same time ,or give another solution. 3Q!

[igorpadykov]

Hi tony

even LCD_RS is pulled up, i.MX28 can drive it since it has sufficient

drive capability, it can switch this signal.

~igor