I’m trying to get my connect a Rainbowduino to a little board I made with a DS1307 real-time clock. I thought I could get everything I needed from the cascading connector (SDA, SCL, VCC, GND) but this doesn’t seem to be working.
One of the confusing things on these boards is that there a several different things all referred to as Vcc. We have the AVR’s Vcc, which is regulated down from the Vcc coming in on either the little white connector or the green terminal block. Then there’s the (switched) Vcc’s for the LED array. And then there’s this other Vcc on the cascading connector.
So what is the Vcc on the cascading connector for? Is it an input? When the Rainbowduino is powered up I seem to see about 0.9V on that pin.
It’ll make my little RTC board much uglier if I have to add a regulator and a flying lead to the green terminal block.