Pinheaders for connecting with the RPi
UART interface: easily connects to UART modules such as RS232, RS485, USB TO UART, etc.
8I/Os interface: easily connects to modules controlled by I/Os, such as 8 Push Buttons, Logic Level Converter, Mix Board, etc.
SPI interface: easily connects to SPI modules such as AT45DBXX Dataflash, L3G4200D Board, etc.
I2C interface: easily connects to I2C modules such as PCF8574 Expansion Board, PCF8563 RTC Board, LSM303DLHC Board, etc.
Character LCD interface: for connecting character LCDs like LCD1602
USB connector: USB TO UART, supported by onboard converter CP2102
Potentiometer: for LCD1602 contrast adjustment
RTC battery holder
PCF8563: onboard RTC chip
32.768K crystal: RTC crystal
CP2102: onboard USB TO UART chip, for debugging
User LEDs jumper
User Keys jumper