Can't see SD card with GPS and LCD

I have a Nano and the SD card (SdFat Library) works fine on it's own.
SD CS = 10, MOSI = 11, MISO = 12, SCK = 13

The same Nano with GPS+LCD without the SD card works fine together.
NEO-6M GPS Rx = D3, Tx = D4
LCD Serial A4, A5

Adding the SD card to the working GPS and LCD, the card is not found.

Can someone please point out where I am going wrong?

If I just unplug the LCD+GPS +5vdc the card is OK again.

I saw some options in the SD card Examples about disabling other items, but what's the point of that as I need all three working. :slight_smile:

Thanks

It's possible both libraries are trying to use the same chip select CS.

aarg:
It's possible both libraries are trying to use the same chip select CS.

A guide on how to find that out and a method to correct it, would be helpful.

The GPS only has two connections to the Nano, Tx, Rx. D4, D5
The LCD only has two connections to the Nano SDA, SCL. A4, A5
The SD has four connections, CS, MOSI, MISO and SCK. D10, D11, D12, D13

I can't see how or where a conflict could be, but then I don't know much about the inner workings, so I ask. :slight_smile:

Power maybe? GPS modules use a lot of current, and if you’ve activated the LCD’s backlight there’s a good change it uses a lot of current too. You might be overloading whatever power supply you’re using. Link to the datasheet for your GPS and LCD modules.

Jiggy-Ninja:
Power maybe?

Thanks for the thought, but I have an external 12vdc-3A supply plugged in. Everything is powered off that. Ran foul of that little problem a while back. :slight_smile:

SalineSolution:
Thanks for the thought, but I have an external 12vdc-3A supply plugged in. Everything is powered off that. Ran foul of that little problem a while back. :slight_smile:

OK. We're tired of guessing. Please post a schematic and some code.

SalineSolution:
Thanks for the thought, but I have an external 12vdc-3A supply plugged in. Everything is powered off that. Ran foul of that little problem a while back. :slight_smile:

I highly doubt you're powering the modules directly off the 12V. They're being regulated by something and if it's the Nano's regulator then it has FAR less capabilities than the wall supply.

The SD card, the GPS, and the LCD would blow out if you connected them directly to 12V. If you mean that you have the 12V supplying the Arduino and get 5V for those devices from Arduino then that's your problem. The regulator on the Arduino can't handle that sort of current.

Delta_G:
OK. We’re tired of guessing. Please post a schematic and some code.

Man, things go off the rails fast around here. I have a regulated 12vdc wall wart and a variable output Buck set for 5vdc output. The buck is rated at 3-16vdc input and at 5vdc output can supply 3-Amps. See pic. Buck is mostly hidden at top of breadboard.

Any chance we can get back to what to actually do to solve the original question?

No guesswork is needed, the Nano is running perfectly well within it’s scope.

With all three devices connected, the GPS+LCD works fine. The SD card shows a “Failed to initialize.”

IF I change nothing other than to unplug the power to the GPS-and-LCD, the SD card works.

It is worth noting that this unchanged-code works fine with a Uno and a GPS shield with built in SD card. But I now need to amke one for a friend and had the GPS/SD in my parts box saving the cost of a Uno + Shield.

Plus I have tried three different SD libraries including Adafruit.

No guesswork is needed on your end because you can see it all. We can't. The issue may be there. But how would we know. Look, if you want help then give the people trying to help you what they say they need to help you. If you already know where the problem is then just fix it. If you don't know what the problem is and want us to try to find it, then you have to let us see it.

Hey, something is wrong with my car. I'm not going to let you see it, or tell you what kind of car it is, or anything else really about it. It's not starting. What's wrong with it? can you tell me? I really need to know because I have places to be.

Delta, not a good analogy as the code works with a Uno+GPS-shield.

The code also works in the Nano when LCD+GPS are connected.
When all three, LCD, GPS and SD are together, it does not work, well, it did not work. With the help of some people on another site, all less interested in code or schematics, the issue is solved.

Schematics are not needed as it is a simple connection as outlined by the pins have already defined.

Glad someone else could guess what your problem was.