Atmel AVR1925 XMEGA-C3 Xplained User manual

APPLICATION NOTE
AVR1925: XMEGA-C3 Xplained Hardware User’s Guide
Atmel XMEGA C
Features
•Atmel®AVR®ATxmega384C3 microcontroller
•OLED display with 128×32 pixels resolution
•Analog sensors
•Ambient light sensor
•Temperature sensor
•Analog filter
•Digital I/O
•Two mechanical buttons
•Two user LEDs, one power LED, and one status LED
•Four expansion headers
•Touch
•Two Atmel AVR QTouch®button
•Memory
•microSD Card
Description
The Atmel AVR XMEGA-C3 Xplained evaluation kit is a hardware platform to
evaluate the Atmel ATxmega384C3 microcontroller.
The kit offers a larger range of features that enables the Atmel AVR XMEGA®user to
get started using XMEGA peripherals right away and understand how to integrate the
XMEGA device in their own design.
Figure 1. XMEGA-C3 Xplained Evaluation Kit
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Table of Contents
1. Related Items..................................................................................... 3
2. General Information ........................................................................... 4
2.1 Preprogrammed Firmware ................................................................................ 4
2.2 Power Supply.................................................................................................... 4
2.3 Measuring the Atmel AVR XMEGA Power Consumption.................................. 4
2.4 Programming the Kit ......................................................................................... 5
3. Connectors ........................................................................................ 6
3.1 Programming Headers ...................................................................................... 6
3.2 I/O Expansion Headers ..................................................................................... 6
4. Peripherals......................................................................................... 8
4.1 microSD Card.................................................................................................... 8
4.2 Atmel AVR QTouch Button ............................................................................... 8
4.3 Mechanical Buttons........................................................................................... 8
4.4 LEDs ............................................................................................................... 8
4.5 OLED Display.................................................................................................... 9
4.6 Analog I/O ......................................................................................................... 9
4.6.1 Temperature Sensor........................................................................... 9
4.6.2 Ambient Light Sensor........................................................................ 12
5. Code Examples................................................................................ 13
6. Revision History ............................................................................... 14
6.1 Revision History of the Document................................................................... 14
6.2 Revision History of the Kit ............................................................................... 14
6.2.1 Revision 2 ......................................................................................... 14

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1. Related Items
The following list contains links to the most relevant documents, software and tools for the Atmel AVR XMEGA-C3
Xplained:
Atmel AVR Xplained products
Xplained is a series of small-sized and easy-to-use evaluation kits for 8- and 32-bit AVR microcontrollers. It consists of
a series of low cost MCU boards for evaluation and demonstration of feature and capabilities of different MCU families.
Atmel Xplained USB CDC driver
The Xplained USB CDC driver file supports both 32- and 64-bit versions of Windows®XP and Windows 7. Driver installs
are not necessary on Linux®operating systems.
XMEGA-C3 Xplained schematics
Package containing schematics, BOM, assembly drawings, 3D plots, layer plots…
AVR1925: XMEGA-C3 Xplained Hardware Users Guide
This document.
AVR1939: XMEGA-C3 Xplained Getting Started Guide
This application note is a getting started guide for the XMEGA-C3 Xplained.
AT01639: XMEGA-C3 Xplained Software User Guide
This application note is a user guide for the XMEGA-C3 Xplained demo software.
AVR1916: XMEGA USB DFU Boot Loaders
This application note is a user guide for the XMEGA USB DFU boot loaders.
Atmel Studio 6
Atmel Studio 6 is a free Atmel IDE for development of C/C++ and assembler code for Atmel microcontrollers.
Atmel FLIP (Flexible In-system Programmer)
BatchISP (FLIP) is a command line tool for programming the flash and EEPROM memories of the AVR and is part of
the FLIP installation. It can be used to communicate with the preprogrammed USB DFU boot loader.
Atmel JTAGICE3
JTAGICE3 is a mid-range development tool for Atmel 8- and 32-bit AVR microcontrollers with on-chip debugging for
source level symbolic debugging, NanoTrace (if supported by the device) and device programming.
Atmel AVR JTAGICE mkII
AVR JTAGICE mkII is a mid-range development tool for Atmel 8- and 32-bit AVR devices with on-chip debugging for
source level symbolic debugging, NanoTrace (if supported by the device), and device programming (superseded by
JTAGICE3).
Atmel AVR ONE!
AVR ONE! is a professional development tool for all Atmel 8- and 32-bit AVR devices with on-chip debug capability. It is
used for source level symbolic debugging, program trace, and device programming. The AVR ONE! supports the
complete development cycle and is the fastest debugging tool offered from Atmel.
Atmel AVR Dragon
AVR Dragon™ sets a new standard for low cost development tools for 8- and 32-bit AVR devices with on-chip debug
(OCD) capability.
IAR Embedded Workbench®for Atmel AVR
IAR™ Embedded Workbench is a commercial C/C++ compiler that is available for 8-bit AVR. There is a 30 day
evaluation version as well as a 4k (code size limited) kick-start version available from their website.

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2. General Information
The Atmel AVR XMEGA-C3 Xplained kit is intended to demonstrate the Atmel AVR ATXmega384C3 microcontroller.
Figure 2-1 shows the available feature on the board.
Figure 2-1. Overview of XMEGA-C3 Xplained Kit
2.1 Preprogrammed Firmware
The ATxmega384C3 on the XMEGA-C3 Xplained is pre-programmed with a boot loader and a default firmware. The
detailed description of the software is available in the AT01639 XMEGA-C3 Xplained Software User Guide.
2.2 Power Supply
The kit needs an external power supply that can deliver 5V and up to 500mA. The actual current requirement for the
board is much less than 500mA but in order to be able to power optional expansion boards this margin is
recommended.
The power can be applied to the board either via the USB connector or on pin 10 on the header J3. The USB connector
is the preferred input because it is then possible to connect expansion boards on top of the J3 header.
The 5V (USB supply voltage) is regulated down to 3.3V with an onboard LDO regulator, which provides power to the
entire board. Expansion top boards that require 5V will get this from the header J3 pin 10.
2.3 Measuring the Atmel AVR XMEGA Power Consumption
As part of an evaluation of the ATxmega384C3, it can be of interest to measure its power consumption. Because the
XMEGA has a separate power plane (VCC_MCU_P3V3) on this board it is possible to measure the current
consumption by measuring the current that is flowing into this plane. The VCC_MCU_P3V3 plane is connected via a
jumper to the main power plane (VCC_P3V3) and by replacing the jumper with an amperemeter it is possible to
determine the current consumption. To locate the power measurement header, refer to Figure 2-1.

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Warning: Do not power the board without having the jumper or an amperemeter mounted since this can cause
latch-up of the Atmel AVR ATxmega384C3 due to current flow into the I/O pins.
2.4 Programming the Kit
The kit can be programmed either from an external programming tool or through an USB boot loader which is pre-
programmed on the device.
The boot loader is evoked by pushing the push button (SW0) during power-on, that is push and hold the button and
hence connect an USB cable to the kit. Programming can be performed through the DFU programmer FLIP.
How a programmer can be connected to the kit is described in Section 3.1.

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3. Connectors
The Atmel AVR XMEGA-C3 Xplained kit has four 10-pin, 100mil headers and one 6-pin 100mil header. The 6-pin
header is used for programming the Atmel AVR ATxmega384C3, and the 10-pin headers are used to access spare
analog and digital pins on the Atmel AVR XMEGA (expansion headers).
3.1 Programming Headers
The XMEGA can be programmed and debugged by connecting an external programming/debugging tool to the PDI
header shown in Figure 2-1.
The grey XMEGA PDI adapter on the Atmel AVR JTAGICE mkII probe has to be used when connecting to the XMEGA-
C3 Xplained board.
The green standoff adaptor nr.3 (ref.A08-0254) on the Atmel AVR ONE! probe has to be used when connecting to the
XMEGA-C3 Xplained board.
Table 3-1. XMEGA Programming and Debugging Interface – PDI
Pin on programming header
PDI
1
DATA
2
VCC
3 -
4 -
5
CLK
6
GND
3.2 I/O Expansion Headers
The Atmel AVR XMEGA-C3 Xplained headers J1, J2, J3, and J4 offer access to the I/O of the microcontroller in order to
expand the board, for example by mounting a top module onto the board.
The header J1 offers digital communication interfaces like UART, TWI and SPI. Table 3-2 shows how the Atmel AVR
XMEGA is connected to the header.
Note: When using TWI note that no pull-ups are mounted on the board from the factory, so it is required to either
enable the internal pull-ups of the device or to mount the external pull-ups on the available footprints (R200 and
R201). Refer to the assembly drawing in the design documentation for the location of these footprints.
Table 3-2. Expansion Header J1
Pin on J1
Name on J1
XMEGA pin
Shared with onboard functionality
1
SDA
PC0
-
2
SCL
PC1
-
3 RXD PC2 -
4
TXD
PC3
-
5
SS
PC4
-
6
MOSI
PC5
-
7
MISO
PC6
-
8
SCK
PC7
-
9
GND
-
-
10
VCC_P3V3
-
-
The header J2 is connected to analog ports of the XMEGA as shown in Table 3-3.

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Table 3-3. Expansion Header J2
Pin on J2
Name on J2
XMEGA pin
Shared with onboard functionality
1
ADC0
PB0
-
2
ADC1
PB1
-
3
ADC2
PB2
-
4
ADC3
PB3
-
5
ADC4
PB4
-
6
ADC5
PB5
-
7
ADC6
PB6
-
8
ADC7
PB7
-
9
GND
-
-
10
VCC_P3V3
-
-
The header J3 is connected to digital ports of XMEGA. Table 3-4 shows the mapping of the XMEGA I/O to J3.
Table 3-4. Expansion Header J3
Pin on J3
Name on J3
XMEGA pin
Shared with onboard functionality
1
PA0
PA0
Light sensor (1)
2
PA1
PA1
Temperature sensor (1)
3
PA2
PA2
Filter output (1)
4
PA3
PA3
Display reset
5
PA4
PA4
6
PA5
PA5
7
PA6
PA6
8
PA7
PA7
9
GND
-
-
10
VCC_P5V0
-
-
Note: 1. Can be disconnected from onboard functionality by cut-straps.
The header J4 offers digital communication interfaces such as UART and TWI but care must be taken because some
pins are also connected to on-board peripherals.
Table 3-5. Expansion Header J4
Pin on J4
Name on J4
XMEGA pin
Shared with onboard functionality
1
SDA
PE0
-
2
SCL
PE1
-
3
RXD
PE2
-
4
TXD
PE3
-
5
SS
PD0
Display data and command select (1)
6
MOSI
PD3
Display and microSD card MOSI
7
MISO
PD2
microSD card MISO
8
SCK
PD1
Display and microSD card clock input
9
GND
-
-
10
VCC_P3V3
-
-
Note: 1. Can be disconnected from onboard functionality by cut-strap (J204).

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4. Peripherals
4.1 microSD Card
The Atmel AVR XMEGA-C3 Xplained has a microSD card standard connector mounted. The SWA is used for detecting
the microSD card. When a microSD card plugs in, the SWA will be pulled to GND. The connection to the MCU is shown
in Table 4-1.
Table 4-1. microSD Card Connection
Pin on XMEGA
microSD card
PD1
SCK
PD3
MOSI
PD2
MISO
PE5 SS
PE4
SWA
4.2 Atmel AVR QTouch Button
The XMEGA-C3 Xplained kit has one Atmel QTouch button and the connection to the Atmel AVR XMEGA is shown in
Table 4-2. The QTouch sensor, a copper fill, is located on the second layer of the board (same as GND layer). The
sensor is shielded by the third layer (VCC layer) and therefore the sensor is not affected by any touches from the back
side of the board.
Table 4-2. QTouch Button Connection
Pin on XMEGA
QButton
PF4
SNS0
PF5
SNSK0
PF6 SNS1
PF7 SNSK1
4.3 Mechanical Buttons
Two mechanical buttons are connected to Atmel AVR XMEGA. All buttons have external pull-ups so there is no need to
activate internal pull-ups in order to use them. When a button is pressed it will drive the I/O line to GND.
Table 4-3. Mechanical Button Connection
Pin on XMEGA
Silkscreen text on PCB
PF1
SW0
PF2 SW1
4.4 LEDs
There are four LEDs available on the board that can be turned on and off. Two yellow LEDs, one green LED (power
indicator LED), and one red LED (status LED). The green and red LEDs are inside the same package and therefore the
colors can be mixed to orange when both are activated. The yellow LEDs and the red LED can be activated by driving
the connected I/O line to GND. The green LED is controlled via a FET and is by default on when the board is powered.
However, this power indicator LED can also be turned off by driving the gate of the FET to GND.

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Table 4-4. LED Connections
Pin on XMEGA
LED
PR0
Yellow LED0
PR1
Yellow LED1
PD4
Red status LED
PD5
Green power indicator LED
4.5 OLED Display
The OLED display on the XMEGA-C3 Xplained board is UG-2832HSWEG04 which comes from WiseChip
Semiconductor Inc. It has a resolution of 128 × 32 pixels. In the design the display is connected via a SPI based
interface. Detailed information about the display can be obtained from the display datasheet.
The connection between the MCU and the OLED display is shown in Table 4-5.
Table 4-5. OLED Display Connection
Pin on XMEGA
QButton
PD0
Data_command
PD1
SCK
PD3
MOSI
PF3
SS
PA3
RESET
4.6 Analog I/O
4.6.1 Temperature Sensor
The temperature sensor circuitry consists of a serial connection of a normal and a NTC resistor. The NTC sensor is
from Murata and some part details are shown in Table 4-6, more information can be obtained from the manufacturer’s
website.
Table 4-6. NTC Characteristics
Global part number
NCP18WF104J03RB
Resistance (25°C)
100kΩ ±5%
B-Constant (25/50°C) (reference value)
4250K ±2%
B-Constant (25/80°C) (reference value)
4303K
B-Constant (25/85°C) (reference value)
4311K
B-Constant (25/100°C) (reference value)
4334K
Table 4-7 shows the temperature vs. resistance characteristic. The values are available from Murata in the datasheet of
the NTC.

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Table 4-7. Resistance vs. Temperature (from Murata)
Temp.
[°C]
NTC resistance
[kΩ]
Temp.
[°C]
NTC resistance
[kΩ]
Temp.
[°C]
NTC resistance
[kΩ]
Temp.
[°C]
NTC resistance
[kΩ]
-30
2197.225
0
357.012
30
79.222
60
22.224
-29 2055.558 1 338.006 31 75.675 61 21.374
-28
1923.932
2
320.122
32
72.306
62
20.561
-27
1801.573
3
303.287
33
69.104
63
19.782
-26
1687.773
4
287.434
34
66.061
64
19.036
-25
1581.881
5
272.500
35
63.167
65
18.323
-24
1483.100
6
258.426
36
60.415
66
17.640
-23
1391.113
7
245.160
37
57.797
67
16.986
-22
1305.413
8
232.649
38
55.306
68
16.360
-21 1225.531 9 220.847 39 52.934 69 15.760
-20
1151.037
10
209.710
40
50.677
70
15.184
-19
1081.535
11
199.196
41
48.528
71
14.631
-18
1016.661
12
189.268
42
46.482
72
14.101
-17
956.080
13
179.890
43
44.533
73
13.592
-16
899.481
14
171.028
44
42.675
74
13.104
-15
846.579
15
162.651
45
40.904
75
12.635
-14
797.111
16
154.726
46
39.213
76
12.187
-13
750.834
17
147.232
47
37.601
77
11.757
-12 707.524 18 140.142 48 36.063 78 11.344
-11
666.972
19
133.432
49
34.595
79
10.947
-10
628.988
20
127.080
50
33.195
80
10.566
-9
593.342
21
121.066
51
31.859
81
10.200
-8
559.931
22
115.368
52
30.584
82
9.848
-7
528.602
23
109.970
53
29.366
83
9.510
-6
499.212
24
104.852
54
28.203
84
9.185
-5
471.632
25
100.000
55
27.091
85
8.873
-4
445.772
26
95.398
56
26.028
86
8.572
-3
421.480
27
91.032
57
25.013
87
8.283
-2
398.652
28
86.889
58
24.042
88
8.006
-1
377.193
29
82.956
59
23.113
89
7.738
Two common approximations can be used to model the temperature vs. resistance characteristic; these are the B
parameter and the Steinhart-Hart equations. Coefficients for both formulas can be calculated from Table 4-7.
When the internal reference VCC/1.6 is used and the ADC is measuring in signed single ended mode the codes in
Table 4-8 can be read from the ADC at the various temperatures. The calculation is based on Table 4-7.
Table 4-8. ADC Codes vs. Temperature (Signed Single Ended Mode with Internal VCC/1.6 Reference)
ADC input [V]
Temp. [°C]
ADC codes
ADC input [V]
Temp. [°C]
ADC codes
2.076
-14
2047
0.347
38
345
2.030
-13
2014
0.334
39
332
1.983
-12
1968
0.321
40
319
1.936
-11
1921
0.309
41
307
1.889
-10
1875
0.297
42
295
1.841 -9 1828 0.286 43 283