iMX25 TFT Interface

[arumugamramasam]

Hi,

I am planning to use iMX25 PDK for my prototype. In that there is already a 5.7 inch 18 Bit Color TFT and touch screen are given, but I would like to interface a new TFT with 24 bit color and without touch screeen. In this regard, I would like to have a reference design (schematics) if anybody already have one.

Thanks,

Arumugam R

[david_dicarlo · Accepted solution]

I am not aware of any designs using a 24-bit color TFT LCD, so there are no reference design schematics that can be provided.

There is no issue to not having a touch screen; this will free up the ADC inputs for use for something else.

What issues are you running into regarding using the new TFT screen you'd like to use? 

[arumugamramasam]

Hi,

I am using a 4.3" TFT whose pin configurations are different from the 5.7" TFT came along with the PDK. So I have introduced an interface board to change the connections of the TFT connector according to the new 4.3" TFT. When I connect the Display, my system is not booting up, which means there is a problem in boot strap pins. Actually I am using SD card to boot and the data lines D0 and D1 are the boot configuration pins for SD card. When I remove these two lines going to the new TFT manually, It is booting. But I don't know what is the impact on the boot pins caused by the new TFT. If you could judge what could be the problem, please let me know.

Thanks,

Arumugam R

[david_dicarlo]

Can you post a partial schematic showing how the boot config pins and the TFT are hooked up?  The TFT connection is probably changing the boot options in some way such that your desired boot is not what the device is seeing on the boot config pins.

Have you looked at how the pins are set up on the MX25 PDK?  The boot config switch bank is typically set up so that the shared peripherals are usable after booting but at boot time, the switch bank is what defines the boot config.

[arumugamramasam]

Hi,

Please find my attached partial schematics of the PDK boot configuration and Display data lines.

I am using the 5.7” with the same configuration, its booting fine, but when I connect a new TFT of 4.3” it is not booting up.

I am booting from SD card and the MEM_CTL0 and MEM_CTL1 pins are set 1 and rest of the pins are set 0 in SW21. Which means, D0 and D1 of the TFT is what set to 1 and rest of the pins are 0 during boot up.

If I remove the D0 and D1 lines manually and prevent them from connecting to the LCD, system is booting up. I don’t understand what makes these two lines to affect my boot sequence.

Please let me know, if you have any idea.

Thanks,

Arumugam R