Copyright
©
Kanda 2013
10
29C256 Pin-outs
24C EEPROM Socket
The board is fitted with a socket for 24C EEPROM Chip. This is an I
2
C device, or in
Atmel speak, a Two Wire Serial Interface (TWI).
The socket is connected to Pin 25 and Pin 26 of the Atmega128. These are SCL and
SDA pins or PD0 and PD1.
The socket layout is shown below.
A full description of the TWI is given in the Atmega128 datasheet. Pull-ups must be
enabled on these lines.
Switches and Bar LED
There is a 10-way bar LED fitted to the board.
•
One LED is Power (labeled ON), and should be on when the board is powered.
•
The next LED is labeled ISP and should be on when the board is in ISP mode.
Note
: The Atmega128 will not run its code if the board is in ISP mode. To exit ISP,
choose Device > Run command or disconnect the ISP lead from the board
•
The other 8 LEDs (0-7) are for user code. They are active low (0 switches them On),
and they are connected to a 10-way header marked LED’S. A short 10-way lead
