AVR364
7
8377B-AVR-11/11
Please note that programming the
tool will erase the boot loader.
Please refer to the Atmel application note, AVR370: MEGA-1284P Xplained
Getting Started Guide, for more details regarding how to program the onboard
microcontrollers.
4.2 I/O expansion headers
There are four available I/O expansion headers in the kit. Because of the low pin
count on the device, the I/O expansion header pins are shared with onboard
functionality. If “clean” expansion ports are needed, cut-straps are available to
remove onboard functionality.
through
show what is shared on
the respective header pins.
Table 4-2.
Atmel MEGA-1284P Xplained I/O expansion header – J1.
Pin J1
ATmega1284P pin
Shared with onboard functionality
1
TWI SDA
PC1
Header J4, board controller
2
TWI SCL
PC0
Header J4, board controller
3
USART RXD0
PD0
Header J4
4 USART
TXD0 PD1
Header
J4
5 SPI
SS
(1)
PB4
Board
controller
6 SPI
MOSI
(1)
PB5
Header J4, DataFlash, board controller
7 SPI
MISO
(1)
PB6
Header J4, DataFlash, board controller
8 SPI
SCK
(1)
PB7
Header J4, DataFlash, board controller
9 GND
-
-
10 VCC_P3V3
-
-
Note:
1. These signals can be disconnected from the board controller by cutting the cut-
straps marked
SPI
on the bottom side of the board.
Table 4-3.
MEGA-1284P Xplained I/O expansion header – J2.
Pin J2
ATmega1284P pin
Shared with onboard functionality
1 ADC0
(1)
PA0
Possible to connect to AREF
2 ADC1
PA1
-
3 ADC2
PA2
-
4 ADC3
PA3
-
5 ADC4
PA4
-
6 ADC5
(2)
PA5
Filter
output
7 ADC6
(2)
PA6
Light
sensor
8 ADC7
(2)
PA7
NTC
sensor
9 GND
-
-
10 VCC_ANA_P3V3 -
-
Notes:
1. AREF with 100nF capacitor to GND can be connected to ADC0 by shorting two
pads marked
EXTERNAL AREF
on the bottom side of the board.
2. These signals can be disconnected from the sensor/filter output by cutting the
cut-straps marked
SENSORS & FILTER
on the bottom side of the board.