If 3 is good then 4 is better

The last post about KiCad (here) was based on the DistoMatic series of boards (eventually there'll be several). I'm trying standardize my connections to simplify the process and allow for greater use.

Previously my pinouts were this:

1. 3v3
2. 5v
3. GPIO
4. Analog
5. GIO
6. Ground

This works fine for the Ping))), MaxBotix, SharpIR, etc. sensors, as they only need voltage, ground, and 1 or 2 signal lines.

I came up with this pinout based on the MaxBotix so that one may be able to connect the sensors so that one can trigger the next one. The trigger-out from sensor #1 would go to the trigger-in to sensor #2.

But I was think that many devices use the SPI (wiki definition) protocol and it wouldn't work with my own spec. That needs Clock, Select, DataIn, DataOut pins, 1 more than what I have available. However, if I remove one of the power lines, then I would have 4 lines for data.

So going forward I'm going to only supply 5v to the my boards. If the sensor or breakout board needs only 3v3, then I can use a voltage divider or a regulator to bring down the voltage.

New pinout:

1. 3v3
2. GPIO
3. GPIO
4. Analog
5. GIO
6. Ground

I am trying to learn from those who came before me --

• Gadgeteer has a 10 pin connector protocol, with 3v3, 5v and GND being standard places
• MikroElectronics has a connector with standardized pinouts for several protocols
• Arduino has standardized pinouts on the connectors for the mCu breakouts.