I'm planning buying a shield to get extended functionality to my Arduino Mega. Here is the link to the shield: https://www.tindie.com/products/Conceptinetics/dmx-shield-for-arduino-rdm-capable/
In the description of the shield, it says this:
Since the library uses the Arduino's primary USART it is not possible to use it together with the Hardware Serial libraries in your project since that will cause conflicting ISR (Interrupt service routine) routines.
Can anyone explain what that means?
Best regards Nelly