I'm using an ESP8266 from Waveshare (universal e-paper driver), with a Sparkfun battery babysitter. I'm finding that when an e-paper screen is connected to the ESP8266 via SPI connections (ribbon cable) - then the battery babysitter is not detectable over I2C, the moment the e-paper screen is disconnected then the I2C device is detectable again. I'm finding this result by running the I2C scanner code, found here: Arduino Playground - I2cScanner
It's not clear to me how connecting one device can prevent another device from being read when they're using different protocols and different connections. Any help would be greatly appreciated.