Congratulations on acquiring the AVR® AT90USBKey. This kit is designed to give
designers a qui ck start to develop code on th e A VR ® and for prot oty ping and testing of
new designs with the AT90USB microcontroller family.
This document describes the AT90USBKey dedicated to the AT90USB AVR
microcontroller. This board is des ig ned to al low an eas y ev alu ation of t he product using
demonstration software.
To increase its demonstrative capabilities, this stand alone board has numerous onboard resources: USB, joystick, data-flash and temperature sensor.
Figure 1-1 . AT90USBKey
AT90USBKey Hardware User Guide1-3
7627A–AVR–04/06
Introduction
1.2 AT90USBKey Features
The AT90USBKey provides the following features:
AT90USB QFN64
AVR Studio® software interface
USB software interface for Device Firmware Upgrade (DFU bootloader)
Power supply flagged by “VCC-ON” LED:
JTAG interface (connector not mounted):
Serial interfaces:
On-board resources:
On-board RESET button
(1)
(2)
– regulated 3.3V
– from an external battery connector (for reduced host or OTG operation)
– from the USB interface (USB device bus powered application)
– for on-chip ISP
– for on-chip debugging using JTAG ICE
– 1 USB full/low speed device/host/OTG interface
– 4+1-ways joystick
– 2 Bi-Color LEDs
– temperature sensor
– serial dataflash memories
– all microcontroller I/O ports access on 2x8pin headers (not mounted)
On-board HWB button to force bootloader section execution at reset.
System clock:
– 8 MHz crystal
Notes: 1. The AVRUSBKey is supported by AVR Studio®, version 4.12 or higher. For up-to-
date information on this and other AVR tool products, please consult our web site.
The most recent version of AVR Studio®, AVR tools and this User Guide can be
found in the AVR section of the Atmel web site, http://www.atmel.com.
2. ATMEL Flip®, In System Programming Version 3 or Higher shall be used for Device
Firmware Upgrade. Please consult Atmel web site to retrieve the latex version of Flip
and the DFU bootloader Hex file if needed.
1-4AT90USBKey Hardware User Guide
7627A–AVR–04/06
2.1Overview
Section 2
Using the AT90USBKey
This chapter describes the AVRUSBKey and all its resources.
Figure 2-1 . AT90USBKey Overvi ew
AT90USBKey Hardware User Guide2-5
7627A–AVR–04/06
Using the AT90USBKey
2.2Power Supply
2.2.1Power Supply Sources
USB powered When used as a US B devic e bus powered application, the AVRUSBKey can be direct ly
Battery powered The ex ternal battery connector should be used when the AT90USBKey is used as a
The on-board power supply circuitry allows two power supply configurations:
from USB connector
from battery connector
powered via the USB VBUS power supply line.
USB host. This mode allows the AT90USBKey to provide a 5V power supply from its
VBUS pin.
– Need of a female battery clip
– Input supply from 8 up to 15V DC (min. 100mA)
Figure 2-2 . P ower supply schematic
J8
2
1
MTA
Ext power supply
VBUS
D3
LL4148
D4
LL4148
D6
LL4148
5V
U4
2
IN
7
SHDN
3
GND
LP3982
U3out=1.25*(1+(R15+R18)/R19)
-
C16
4.7uF
220nF
C17
OUT
OUT
FAULT
CC
SET
VBAT
1
4
8
6
5
33nF
C15
1
2
U5
IN
GND
LM340
OUT
100k 1%
R19
124k 1%
3
100nF
C18
VCC3
VCC3
R15
R18100k 1%
2-6AT90USBKey Hardware User Guide
7627A–AVR–04/06
2.2.2VBUS Generator
Using the AT90USBKey
When using the AT90USB microcontroller in USB host mode, the AT90USBKey should
provide a 5V power supply over the VBUS pin of its USB mini AB connector.
A couple of transistors allows the UVCON pin of the AT90USB to control the VBUS
generation (See Figure 2-3). In this mode the AT90USBKey is powered by external
battery power supply source.
Figure 2-3 . VBUS generator schematic
FDV304P/FAI
UVCON
5V
R24
M1
10k
R25
Q1
BC847B
100k
-
C19
4.7uF
VBUS
2.2.3“POWER-ON“ LED
The POWER-ON LED (“D1”) is always lit when power is applied to AVRUSBKey
regardless of the power supply source.
AT90USBKey Hardware User Guide2-7
7627A–AVR–04/06
Using the AT90USBKey
2.3Reset
Although the AT90USB has its on-chip RESET circuitry (c.f. AT90USB Datasheet,
section “System Control and Reset), the AVRUSBKey provides to the AT90USB a
RESET signal witch can come from two different sources:
Figure 2-4 . Reset Impleme n tatio n
VCC
2.3.1Power-on RESET
2.3.2RESET Push Button
2.3.3Main Clock XTAL
R6
47k
RST
C8
220nF
RESET
The on-board RC network acts as power-on RESET.
By pressing the RESET push button on the AVRUSBKey, a warm RESET of the
AT90USB is performed.
To use the USB i nterface of the AT90USB, the clock s ource s hou ld a lways be a crystal
or external clock oscilla tor (the internal 8MHz RC oscilla tor can not be used to operate
with the USB interface). Only the following crystal frequency allows proper USB
operations: 2MHz, 4MHz, 6MHz, 8MH z, 1 2 MHz, 1 6 MHz. The AT90USBKey come s w ith
a default 8MHz crysta l os c illator.
2-8AT90USBKey Hardware User Guide
7627A–AVR–04/06
2.4On-board Resources
2.4.1USB
The AVRUSBKey is supplied with a standard USB mini A -B receptacle. The mini AB
receptacle allows to connect both a mini A plug or a mini B plug connectors.
Figure 2-5 . USB mini A-B Receptacle
J3
1-V_BUS
5-GND
USB_MiniAB
2-D-
3-D+
4-ID
SHIELDSHIELDSHIELDSHIELD
VBUS
CR1
VBUS
CR2
R2 22
R3 22
C7
1uF
R4 0
Using the AT90USBKey
DD+
GND
UCAP
VBUS
GND
VBUS
UID
2.4.2Joystick
When connecte d to a mini B plug, the AT90USB operates as an “US B device” (the ID
pin of the plug is unconnected) and when conne cted to a mini A plug, t he AT90USB
operates as a “USB host” (the ID pin of the A plug is tied to ground).
The 4+1 ways joystick offers an easy user interface implementation for a USB
application (it can emulate mouse movements, keyboard inputs ...).
Pushing the push-button causes the corresponding signal to be pulled low, while
releasing (not pressed) causes an H.Z state on the signal. The user must enable
internal pull-ups on the microcontroller input pins, removing the need for an external
pull-up resistors on the push-button.
Figure 2-6 . J oystick Schematic
PB[7..0]
PB[7..0]
SW3
SW3
SW3
1
1
1
2
2
2
TPA511G
TPA511G
TPA511G
Com1
Com1
Com1
Com2
Com2
Com2
Select
Select
Select
Left
Left
Left
Up
Up
Up
Right
Right
Right
Down
Down
Down
PB5
PB5
PB5
5
5
5
PB6
PB6
PB6
7
7
7
PB7
PB7
PB7
3
3
3
PE4
PE4
PE4
6
6
6
PE5
PE5
PE5
4
4
4
PB[7..0]
PE[7..0]
PE[7..0]
PE[7..0]
AT90USBKey Hardware User Guide2-9
7627A–AVR–04/06
Using the AT90USBKey
2.4.3LEDs
The AT90USBKey includes 2 bi-color LEDs (green/red) implemented on one line. They
are connected to the high nibble of “Port D” of AT90USB (PORTD[4..7]).
To light on a LED, the corresponding port pin must drive a high level. To light off a LED,
the corresponding port pin must drive a low level.
Figure 2-7 . LEDs Implementation schematic
LEDs
D2
D5
Table 2-1 . Leds references
LED ReferenceAT90USB ConnectionColor
D2PORTD.4Red
D5PORTD.6Green
In-line Grouped LED s
R141k
R171k
R221k
R231k
PORTD.5Green
PORTD.7Red
PD4
PD5
PD6
PD7
PD[7..0]
2.4.4Temperature Sensor
The temperature sensor uses a thermistor (R29), or temperature-sensitive resistor. This
thermistor have a negat ive t emperatu re c oefficient (NTC ), mea ning the resistance goes
up as temperature goes down. Of all passive temperature measurement sensors,
thermistors have the highest sensitivity (resistance cha nge per degree of temperat ure
change). Thermistors do not have a linear temperature/resistance curve.
The voltage over the NTC can be found using the A/D converter (connected to channel
0). See the AT90USB Datasheet for how to use the ADC. The therm istor value (R
T) is
calculate with the following expression:
R
RHV
T
Where:RT = Thermistor value (Ω) at T temperature (°Kelvin)
⋅()VCC V
ADC0
H = Second resistor of the bridge -100 KΩ ±10% at 25°C
R
ADC0 = Volt age value on ADC-0 input (V)
V
VCC = Board power supply
2-10AT90USBKey Hardware User Guide
7627A–AVR–04/06
–
()⁄=
ADC0
Using the AT90USBKey
The NTC thermistor used in AT90USBKey has a resistance of 100 KΩ ±5% at 25°C (T0)
and a beta-value of 4250 ±3%. By the use of the following equation, the temperature (T)
can be calculated:
T
Where:RT = Thermistor value (Ω) at T temperature (°Kelvin)
R
T
⎛⎞
ln
⎝⎠
-------
R
------+
T
0
β
0
β
-------------------------------=
ß = 4250 ±3%
0 = 100 KΩ ±5% at 25°C
R
0 = 298 °K (273 °K + 25 °K)
T
The following cross table also can be used. It is based on the above equation.
Table 2-2 . Thermistor Values versus Temperature
For mass-stora g e cla ss dem onstration purp o se , th e AT90 USBKe y p r o vides two on-chip
serial Flash memories (AT45DB642D) connected to the AT90 USB Serial Port Interface
(SPI).
PB[7..0]
VCC3
PE0
PB1
PB2
PB3
RESET
R9
100k
The data-flash chip select signals are connected to PortE bit 0 and bit 1 of the AT90USB
(See Figure 2-9).
Figure 2-9 . On-board data flash schematic
VCC3
R10
U2
1
SI
2
SCK
3
RESET
4
CS
AT45DB642D C ASON 8
SO
GND
VCC
WP
VCC3
8
7
6
5
R11
100k
PE1
PB1
PB2
PB3
RESET
100k
U3
1
SI
2
SCK
3
RESET
4
CS
AT45DB642D C ASON 8
SO
GND
VCC
WP
VCC3
8
7
6
5
R12
100k
2-12AT90USBKey Hardware User Guide
7627A–AVR–04/06
2.5In-System Programming
2.5.1Programming with USB bootloader: DFU (Devi ce Firmware Upgrade)
AT90USB part comes with a default factory pre-programmed USB bootloader located in
the on-chip boot section of the AT90USB. This is the easiest and fastest way to
reprogram the device directly over the USB interface. The “Flip” PC side application, is
available from the Atmel website, offers a flexible an user friendly interface to reprogram
the application over the USB bus.
The HWB pin of the AT90USB allows to force the bootloader section execution after
reset. (Refer to AT90USB datasheet section “boot loa der support”). To force bootloader
execution, operate as follow:
Press both “RST” and “HWB” push buttons
First release the “RST” push button
Release the “HWB” push button
For more information about the USB bootloader and “Flip” application, please refer to
the “USB bootloader datasheet document” and “Flip’s user manual”.
Using the AT90USBKey
Note:The HWB pin is active only if the HWBE fuse is set (def ault factory conf iguration).
2.5.2Programming with A VR JTAGI CEmKII
The AT90USB can be programmed using specific JTAG link. To use the AVR
JTAGICEmkII with an AT90USBKey an optional HE10 connector should be soldered to
J9 footprint. Then the JTAG probe c an be con nected t o the AT90USBKey as shown in
Figure 2-10.
Note:When the JTAGEN Fuse is unprogrammed, the four TAP pins are normal port pins, and
the TAP controller is in reset. When programmed, the input TAP signals are internally
pulled high and the JTAG is enabled for Boundary-scan and programming. The
AT90USB device is shipped with this fuse programmed.
AT90USBKey Hardware User Guide2-13
7627A–AVR–04/06
Using the AT90USBKey
Figure 2-10 . Connecting AVR JTAG ICE to AVRUSBKey
The Flash, EEPROM and all Fuse and Lock Bit options ISP-programmable can be
programmed individually or with the sequential automatic programming option.
Note:See AVR Studio® on-line Help for informati on.
2.6Debugging
2.6.1Debugging with AVR JTAG ICE mkII
The AT90USBKey can be used for debugging with JTAG ICE MK II.
Connect the JTAG ICE mkII as shown in Figure 2-10, for debugging, please refer to
AVR Studio® Help information.
When using JTAG ICE MK II for debugging, and as AT90USB parts are factory
configured with the higher security level set, a chip erase operation will be performed on
the part before debugging. Thus the on-ch ip flash bootloader will be erased. It can be
restored after the debug session using the bootloader hex file available from ATM EL
website.
2-14AT90USBKey Hardware User Guide
7627A–AVR–04/06
Troubleshooting Guide
Figure 3-1 . Troubleshooting Guide
ProblemReasonSolution
The Green “VCC-ON”
LED is not on
No power supply
AVRUSBKey does not
work
Section 3
Verify the power supply source (check
battery char ge or USB connection).
The A T90USB cannot be
programmed
AVR Studi o does not
detect the AVR JTAG
ICE.
The A V R JTAG ICE
probe is not
connected
The memory lock bits
are programmed
The fuse bits are
wrongly programmed
Can not connect to
USB bootloader
Serial/USB cable is
not connected, or
power is off
PC COM port is in
use
Connect the JTAG ICE 10-PIN header to
the correct AVRUSBKey JTAG header
(page 13)
Erase the memory before programming
with JTAG ICE.
Check the fuse bits with JTAG ICE
Force bootloader execution with HWB
under reset.
USB bootloader erased after a JTAG
debugging session: reprogram the USB
bootloader with JTAG.
Connect seri al cable to RS232 (STK5 00 AVR ISP) and check power connect ions
Connect serial cable to USB (JATG ICE
MKII, AVR ISPmkIIl) and chec k power
connections
Disable other programs that are using
PC COM port.
Change PC COM port
AVR Studio does not
detect COM port.
AT90USBKey Hardware User Guide3-15
Disable COM port auto-detect ion in AVR
St udio file menu. Force COM port to
correct COM port
7627A–AVR–04/06
Section 4
Technical Specifications
System Unit
– Physical Dimensions .....................................................L=90 x W=30 x H=8 mm
– Weight...........................................................................................................12 g
Operating Conditions
– Internal Voltage Supply .... ...........................................................................3.3V
– External Voltage Supply .........................................................................8V -15V
Connections
– USB Connector......................................................................Mini AB receptacle
– USB Communications .......................................................Full speed/low speed
– JTAG Connector....................................................Footprint for HE10 connector
– All ports connectors.............................................................J1, J2, J4, J5, J6, J7
– Battery connector....................................................................... MTA right angle
AT90USBKey Hardware User Guide4-16
7627A–AVR–04/06
Section 5
Technical Support
For Technical support, please contact avr@atmel.com. When requesting technical
support, please include the following information:
Which target AVR device is used (complete part number)
Target vo ltage and speed
Clock source and fuse setting of the AVR
Programming method (ISP, JTAG or spec ific Boot-Loader)
Hardware revisions of the AVR tools, found on the PCB
Version number of AVR Studio. This can be found in the AVR Studio help menu.
PC operating system and version/build
PC processor type and speed
A detailed description of the problem
AT90USBKey Hardware User Guide5-17
7627A–AVR–04/06
Section 6
Complete Schematics
On the next pages, the following documents of AT90USBKey are shown:
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Tel: 1(719) 57 6-3300
Fax: 1(719) 540-1759
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Tel: (33) 4-76-58-30-00
Fax: (33) 4-7 6-58-3 4-80
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