"@ Mark; You may very well be correct. The ATMega series has internal diode protection on it's GPIO pins, both for over voltage (clamp to power) and for under voltage (clamp to ground). The relay uses 10mA at 5V, the AVRs internal diodes can probably…"
"@ Mark; The datasheet doesn't mention an internal diode, nor does it give an equivalent circuit diagram :( However, it does mention the release times with and without a diode in parallel, so I assume it doesn't have one. Since this relay is powered…"
"For the sake of completeness, here's an updated diagram:
There are still a few caps I couldn't label due to a lack of space, so here's some descriptions to go along with the picture.
- The relay is probably a Tyco IM03GR, in which case, you may…"
Here are the parts that I could identify:
- FT245RL (top left)
- PCA9306 (Converts the 5V I2C signals to 3.3V for Jordi's SCP1000 board)
- LY530ALH (near the ADC)
- LPR530AL (near the ADC)
- ADXL335 (near the ADC)
- MAX147…"