Philips I2c, or Inter-Integrated Circuit, is a 2-wire serial communication with unique start-and-stop conditions, bi-directional communication, full synchronization, and multimaster operation.

I2c is primarily used to communicate between two IC's, or multiple IC's in close proximity (13 feet, at 100K bit/sec). By using Philips I2c Bus Extender, P82B715, the communication is increased by a factor of 10 (excess of 130 feet). This enables I2c to be used in applications between a central control box and remote locations.

The Philips proprietary I2c serial bus protocol is an industry standard found in more than 100 products and licensed to more than 30 IC manufacturers.



 Here you will find my I2c-baseboard and my I2c-breadboard. The first one a board with four I2c-PCF8574(A) IC's for extra I/O. The second one is a board with breadboard-space, and all connectors to connect to the first board.

Furthermore a connector with the analog-input P6.0-P6.7, I2c-signals SDA - SCLK and reference voltage connection VAREF and VAGND.

The I2c-baseboard with lots of room for your own design.

The I2c-breadboard



The two boards combined.

Depending on the type of PCF8574(A) you are using on the 515/535-mainboard you can use the following I2c-addresses:

Address: Board: Type of
PCF8574		 Straps:
40H I2c-baseboard #1   Jumper.bmp (1666 bytes)Jumper.bmp (1666 bytes)Jumper.bmp (1666 bytes)
42H I2c-baseboard #1   Jumper.bmp (1666 bytes)Jumper.bmp (1666 bytes)noJump.bmp (1666 bytes)
44H I2c-baseboard #1   Jumper.bmp (1666 bytes)noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)
46H I2c-baseboard #1   Jumper.bmp (1666 bytes)noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)
48H I2c-baseboard #2   noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)Jumper.bmp (1666 bytes)
4AH I2c-baseboard #2   noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)noJump.bmp (1666 bytes)
4CH I2c-baseboard #2   noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)
4EH I2c-baseboard #2   noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)
70H LCD-display connection on 80C535-mainboard A  
72H Keyboard conn. on 80C535-mainboard A  
74H I2c-baseboard #3 A Jumper.bmp (1666 bytes)noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)
76H I2c-baseboard #3 A Jumper.bmp (1666 bytes)noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)
78H I2c-baseboard #4 A noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)Jumper.bmp (1666 bytes)
7AH I2c-baseboard #4 A noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)noJump.bmp (1666 bytes)
7CH I2c-baseboard #4 A noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)Jumper.bmp (1666 bytes)
7EH I2c-baseboard #4 A noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)noJump.bmp (1666 bytes)

The PCF8574(A) can drive 8 LED's directly (check the documentation) or you can use this IC for input.