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Arduino Uno versus Mega2560

Posted: Tue Apr 05, 2022 4:30 pm
by prestonpressure
I am able to get the Basic Arduino EVE Demo working with an Arduino Uno board. But nothing happens when I use a Mega2560 board. I need the Mega2560 board for my project.
I am using the EVE2 Scoodo shield. The display is an EVE3-70G-BLM-TPC-F32.
I am powering the Uno and Mega2560 boards with 12VDC.

I get the Basic Arduino EVE Demo to load to the Mega2560 but other than the red LED power light on the back of the display, nothing else happens. I have tried more than one Mega2560 with the same result.
Any advice?

Re: Arduino Uno versus Mega2560

Posted: Wed Apr 06, 2022 12:51 pm
by Rudolph
The shield is not compatible with the Mega2560, there is no SPI on the pins the Uno is using for SPI.
You could either use jumper cables between the shield and the Mega2560, or use software-SPI.

Re: Arduino Uno versus Mega2560

Posted: Thu Apr 07, 2022 7:15 am
by prestonpressure
Yes. That is what I discovered. There is a way to change this in software, but it would be managing the SPI with software instead of the UART and the results are likely to be poor. The UART SPI connects to the Mega pins 50, 51, and 52. The Uno-to-Mega connection pins are: 11>51 12>50 13>52. The only solution is to do a physical connection. The attached pictures illustrate how I resolved this. The three shield pins 11, 12, and 13 are bent inward and connected with a plug and wires to the Mega pins 51, 50 and 52. The display is now working with this modification.

Re: Arduino Uno versus Mega2560

Posted: Tue May 03, 2022 6:16 pm
by Henry
Thank you for posting your solution!