SD card on TFT sd7735 breakout "...initialization failed"

[wylbur]

hi Adafruit,

I'm working with Adafruit's 160x128 TFT display breakout with the SD card. The display works fine, but my attempts to use the card have failed.

I've wired the breakout to my Teensy 4 by the hardware SPI (MISO, SCK, MOSI) and the CARD_CS pin to the T4's pin 10 (I've also tried pin 4, adjusting the code appropriately, no change). I inserted a SanDisk ExtremePlus 32G microSD card formatted as FAT32. I'm powering the TFT via the T4's 3.3v rail which is ok for 250mA.

When I run the SD library's CardInfo sketch, I get "Initializing SD card...initialization failed."

I saw a note in the TFT's howto tutorial that this board isn't great for data logging. Is that true? (if yes, sad, that was my intended use) I'm a little stuck, any suggestions would be v welcome -- wylbur.

[mikeysklar]

Hi wylbur,

I've seen a lot of posts in regards to getting going with these.

Let's starting with photos of your wiring and soldering to make sure that look right.

[wylbur]

hi mikeysklar,

Sure! I've attached photos of the soldering on the breakout board, the wiring on the board, and the wiring on the breadboard. Just to confirm, here's the wiring:

Code: Select all

TFT -->  T4
lite     3.3v
MISO     p12
SCK      p13
MOSI     p11
TFT_CS   p10
CARD_CS  p4
D/C      p9
RESET    p8
VCC      3.3v
Gnd      Gnd 

I'd love any thoughts you might have -- wylbur.

[mikeysklar]

Thank you for the photos. Can you send me one more "above" shot of the Teensy wiring on the breadboard (birds eye view).

[wylbur]

Sure thing, hope one of these has the right angle -- wylbur.

[mikeysklar]

Okay, your wiring looks good with all the cables in appropriate locations and gnd/3.3v rails in place.

Which code demo are you starting with? Can you post it here so I can confirm the pins are configured correctly for a Teensy 4?

[wylbur]

Sigh.

But in a good way: as I prepared to post code I was using, I assumed it wouldn't work. But then I tried SD::CardInfo and it worked. Then I tried SD:Datalogger, and it worked. And I adapted the example code to my application, and it worked.

I imagine that I had a wiring error but as I put it back together, I made the last fix but didn't redo the test. Apologies! And thanks for nudging me to do the basic debugging -- wylbur.

[mikeysklar]

With this many connections wiring is definitely a risk. I usually put the devices on the same breadboard and custom cut each wire to try and reduce the confusion factor.