I'm building a project that requires reading from an SD card and after double-checking connections, I keep getting an "SD init failed!" error code.
Is there a script I can use to test if my SD card module is communicating with the Arduino Mega, to determine if maybe my module is bad?
I don't know of a way to test just the module. But you could try running one of the SD library examples, such as CardInfo, with an SD card inserted in the module. Just be sure the CS pin selection is the same in the sketch and in hardware.
Beginner question: how would I find/install that? Is there somewhere on the forum, or do you mean a sample library within the Arduino software?
I’m still running v1.8.8 of the IDE, but this probably hasn’t changed. You pull down the File menu, then Examples, then SD. There are several examples, including CardInfo. But you’re going to have to do some research on the Mega SPI pins. I believe they are 50 through 53. You’ll have to change the CardInfo.ino sketch, which has the CS (aka SS) pin as pin 4, to whatever you are using on the Mega, probably 53. Then pull down the Tools menu and select the right board and port.
I’ve never actually used a Mega. Maybe someone who has will give you better information.
Those are the pins I have from my schematics, so I'd assume 50-53 are the right ones. Where exactly would I change that value in the sketch? The line that says "const int chipSelect = 4;" I would in theory change to "const int chipSelect = 53;"?
Yes, I think so. If it still doesn't work, post your schematic and a link to the SD module you're using.