Atmel AVR32918: UC3-A3 Xplained Hardware User’s Guide [APPLICATION NOTE]
32159C
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AVR
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07/2012
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One dual LED is mounted near the USB connector. It has one green LED which is used to indicate power and one red
LED that can be used for other purposes. The green LED will be active when power is applied to the board but it can be
disabled by software from the AT32UC3A3256 device if needed. The red LED is active low and the green LED is active
high.
5.3
Analog I/O
A RC filter and a NTC temperature sensor are connected to ADC0 and ADC1 respectively. These analog sensors are
used as input to the ADC but it is also possible to disconnect them by cutting the cut-straps on the bottom side of the
board.
The RC filter (1. order low-pass) has an approximate 3dB cut-off frequency of 159Hz. The input to the RC filter is one of
the UC3 GPIO pins that can be configured to output a PWM signal to the RC filter. This can be used to generate a DC
voltage on the output of the RC filter which can be measured on the ADC. As this is a 1. order filter, the ripple on the DC
voltage is proportional to the input frequency. A higher input frequency will give lower ripple on the output.
5.4
Touch
The UC3-A3 Xplained kit has one QTouch button and one QTouch slider; both are connected to GPIO pins on the
AT32UC3A3256.
Table 5-1. UC3 touch connections.
Touch sensor onbard reference
QTouch method pin name
UC3 GPIO pin
CH1
SNSK1
98
CH1
SNS1
99
CH2
SNSK2
100
CH2
SNS2
101
CH3
SNSK3
102
CH3
SNS3
103
CH4
SNSK4
104
CH4
SNS4
105
6.
Included code example
The example application is based on the Atmel Software Framework (ASF) found ondocumentation, help and examples on the drivers used, please take a look at the website. The Atmel Software
Framework is also included in Atmel Studio.
6.1
Compiling and running
The code examples that can be found in ASF can be compiled by running make on the makefile included in the project
or by opening up the project in IAR™ and compiling the project within IAR.
7.
Revision history
To identify the revision of the Atmel UC3-A3 Xplained kit, locate the bar-code sticker on the back side of the board. The
first line on the sticker shows the product ID and the revision. For example “A09-1053/10” can be resolved to ID=A09-
1053 and revision=10.
