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no pull down on LCD_RS

Question asked by Jed Kropp on Mar 15, 2016
Latest reply on Mar 16, 2016 by igorpadykov

I have a question about the LCD_RS pin on the i.MX28. 


If the ENABLE_PIN_BOOT_CHECK is blown and LCD_RS is NOT pulled down, and is connected to an LCD(LCD_DOTCLK),  is the boot mode guaranteed to be determined by the OTP eFuse bits in ROM0 (HW_OCOTP_ROM0:0x8002C1A0:31:24)?  There is not a pull-up on LCD_RS either.


We have a module with a i.MX28 chip that is used in two different base-boards.  One base-board pulls down LCD_RS and the other does not.  Both base-boards use this pin for LCD_DOTCLK for it's display.  Both of these configurations are reading the OTP eFuse bits, which is the way we expect them both to operate.  I need to know if the base-board that doesn't pull down LCD_RS is guaranteed?  The reason we need this to operate without a pull down is for cross-base-board compatibility.  We have thousands of boards without a pull down on LCD_RS that originally did not need the ENABLE_PIN_BOOT_CHECK to be blown, but now require it.