Mega Discrepancy?

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peak@sparkfun
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Mega Discrepancy?

Post by peak@sparkfun » Thu Jul 18, 2013 9:56 am

Hi All,

I've got this display: http://www.electrokit.com/2-4-tft-lcd-t ... uino.49420
It's working on Standard UNO (5V) but just lit up on the Sparkfun Mega Pro (http://www.electrokit.com/mega-pro-5v-a ... belt.49198).
I've cut the 3,3V feed as it is connected to 5V on Sparkfun Mega Pro 5V. Yes, Works on Uno with the cut! Tested all relevant outputs on the Mega, Working !

Anyone got a clue?

Regards
Peter

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Ross Robotics
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Re: Mega Discrepancy?

Post by Ross Robotics » Thu Jul 18, 2013 2:53 pm

So what's your question?

Check the pin mappings because the Uno is different from the Mega.
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peak@sparkfun
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Joined: Thu Jul 18, 2013 9:52 am

Re: Mega Discrepancy?

Post by peak@sparkfun » Thu Jul 18, 2013 10:41 pm

Well, apart from the above mentioned difference between 3,3 and 5V pins, the pin mappings are identical regading the pins used by the display.

Regards
Peter

peak@sparkfun
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Re: Mega Discrepancy?

Post by peak@sparkfun » Fri Jul 19, 2013 5:03 am

Does the Sparkfun Mega Pro use different CPU pins to the corresponding digital and analog pins than the Arduino Mega? If so, that'd explain the discrepancy. Anyone knows?

Regards
Peter

n1ist
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Re: Mega Discrepancy?

Post by n1ist » Fri Jul 19, 2013 8:15 am

The mega pro 5v page is https://www.sparkfun.com/products/11007
You can find the schematics there to check the pinout. There are also some comments about a wrong crystal being loaded; if that's the case, timing could be off.

peak@sparkfun
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Re: Mega Discrepancy?

Post by peak@sparkfun » Sat Jul 20, 2013 5:43 am

Got it working now. For further reference:
Two things needed:
1. Uncomment USE_UNO_SHIELD_ON_MEGA in HW_Atmega1280.h
2. Change UTFT myGLCD(ITDB24E_8, 19, 18, 17, 16); to UTFT myGLCD(ITDB24E_8, A5, A4, A3, A2);

Regards
Peter

MBlank
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Re: Mega Discrepancy?

Post by MBlank » Tue Mar 10, 2015 12:27 pm

Hello,

I noticed that you were having issues with sparkfun's mega board working with a tft screen, but you were able to solve your problem. I am having a very similar issue using their mega pro mini 3.3V board. I tried following your solutions to the problem, but the libraries aren't the same. The chip that's used for this board is ATmega2560, so have you had any experience using it with a tft screen?

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