User manual

Atmel AVR32918: UC3-A3 Xplained Hardware User’s Guide [APPLICATION NOTE]

32159C−AVR−07/2012

Table 3-5. UC3 I/O expansion header – J4.

Pin J4 UC3 pin Shared with onboard functionality

1 TWI1 SCL

(1)

PA14/PA15 USART1 RTS

2 TWI1 SDA

(1)

PA15/PA12 USART1 CTS

3 USART1 RXD PA05 -

4 USART1 TXD PA06 -

5 SPI0 CS3 PA07 -

6 SPI0 MOSI PA10 Serial flash/DataFlash

7 SPI0 MISO PA11 Serial flash/DataFlash

8 SPI0 SCK PA08 Serial flash/DataFlash

9 GND - -

10 VCC_P3V3 - -

Note: 1. See known issues Section 7.1.1.1 Swapped TWI SCL and TWI SDA on header J4.

4. Memories

The Atmel UC3-A3 Xplained has an external SDRAM memory mounted on the board. There are also footprints

available for adding either an industrial standard or a proprietary Atmel DataFlash serial flash.

Note: The footprints share the same SPI lines including the chip select, and so it is not possible to mount a device on both

footprints at the same time.

Table 4-1. Compatible devices for the footprints.

Atmel AT45DB Atmel AT25DF

AT45DB64D2-CNU AT25DF641A-SH

AT45DB321D-MWU AT25DF321A-SH

AT45DB161D-SS AT25DF161-SH

AT45DB081D-SS AT25DF081-SSH

AT45DB041D-SS AT25DF021-SSH

AT45DB021D-SS

AT45DB011D-SS

5. Miscellaneous I/O

5.1 Mechanical button

The board is equipped with one mechanical button. Because the button is used to enter bootloader mode it has a pull-

up mounted, this means it is not necessary to use the pull-up in the UC3 to detect the status of the button.

5.2 LEDs

The Atmel UC3-A3 Xplained has four yellow LEDs which are connected to the Atmel AT32UC3A3256 and all of them

are active low.