One of the biggest (and most noticeable) differences is now there's a 40-pin GPIO port instead of 26-pin
First thing to notice, the top 26 pins of the 40-pin connector are the same as the original
That means that most/many Pi Plates that plug into the Model B will plug into the B+ just fine. They wont sit in the same location - they'll be slid down just a bit but electrically-wise its the same.
That means that most/many Pi Plates that plug into the Model B will plug into the B+ just fine. They wont sit in the same location - they'll be slid down just a bit but electrically-wise its the same.
New GPIOs
For people who love to attach sensors, buttons, displays and other accessories, there's good news: theres 9 more GPIO pins! Yay!
There's also a pair of odd pins, ID_SD and ID_SC. The note says they are reserved for PiPlate ID EEPROM! What's that mean? Sounds like the Pi foundation took a hint from the BeagleBone Black design for BBB capes. The BBB capes all have a shared I2C bus for a classic 24LC type EEPROM. When the BBB boots, it reads the EEPROM and configures the bone inputs and outputs and kernel modules, etc. based on the EEPROM contents.
The ID pins are likely the same, its a secondary I2C port that looks just for these identifing EEPROMs. That way the Pi knows what Pi Plate is attached.
There's also a pair of odd pins, ID_SD and ID_SC. The note says they are reserved for PiPlate ID EEPROM! What's that mean? Sounds like the Pi foundation took a hint from the BeagleBone Black design for BBB capes. The BBB capes all have a shared I2C bus for a classic 24LC type EEPROM. When the BBB boots, it reads the EEPROM and configures the bone inputs and outputs and kernel modules, etc. based on the EEPROM contents.
The ID pins are likely the same, its a secondary I2C port that looks just for these identifing EEPROMs. That way the Pi knows what Pi Plate is attached.
