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Xinyuan-LilyGO / LilyGo-T-Call-SIM800

https://www.aliexpress.com/item/33045221960.html
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TTGO ESP32 SIM800L - I2C comms weirdness #62

Closed BillyGriffiths closed 4 years ago

BillyGriffiths commented 4 years ago

This is probably not the place to ask this, and if so, please point me in the right direction.

I have an OLED (SSD1306) connected to the board. VDD->3.3V, GND->GND, SCL->PIN22, SDA->PIN21. Running an I2C scan indicates 2 devices, one being power management (0x75) and the other OLED (0x3c). When the display is not configured, I can read power data without any problems, but when I add the display power data is erratic indicating communication problems with 2 devices on the same bus.

Do I need to manually pull-up SCL and SDA, or does the board have adequate internal resistors? I can't seem to find a schematic. (Info on board: BLYNK v1.3 - 20190610)

BillyGriffiths commented 4 years ago

I added discreet pull-ups and my problems were resolved.