ESP8266 Community Forum

Anyone had any success getting a DS1307 RTC to work on I2C, with a Lolin NodeMCU ? (With Arduino IDE)
I got it wired up, configured D2 & D3 for SDL & SCL, and ran I2C scanner. I could see 3x device, although only the Tiny RTC connected. None were correctly addressed.
When I tried the examples, I got weird values.
I then tried the same code and same Tiny RTC on my Uno. All worked fine.
Any help or guidance much appreciated

UPDATE........
I got it working. Had to remove R2 & R3 from the Tiny RTD board (They tie SDA & SCL to 5V!!!), and use the "Wire.begin(x.y)" instruction - where x&y are the GPIO numbers (Not the NodeMCU pin numbers)

Any further updates on this?

I purchased the MakerFocus boards at Amazon and got it to work fine with a uSD card reader on HSPI and a DS3231 Precision RTC (same pins and library as the DS1307). Had to change the CS or Chip Select for the HSPI for the uSD reader from pin 4 to pin 15 in the Arduino IDE to get it to work.

https://smile.amazon.com/gp/product/B01IK9GEQG


But when I got the LoLin NodeMCU version 3, V3, I cannot get the uSD card interface on HSPI to work.
https://www.amazon.com/gp/product/B07B9Q6ZWK

The code says card failed to initialize.
Same code, same wiring as the MakerFocus NodeMCU, same libraries and Arduino IDE 1.8.5 with latest ESP8266 -12E core in the board manager.

I'm stumped for now.