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STK525
User Manual
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ATMEL STK525 User Manual

STK525
.............................................................................................
Hardware User Guide
Section 1
Introduction...........................................................................................1-3
1.2 STK525 Starter Kit Features.....................................................................1-4
Section 2
Using the STK525.................................................................................2-6
2.2 Power Supply............................................................................................2- 7
2.3 RESET....................................................................................................2-10
2.4 AT90USBxxx AVR Microcontroller..........................................................2-11
2.5 Serial Links .............................................................................................2-11
2.6 On-board Resources...............................................................................2-14
2.7 STK500 Resources.................................................................................2-19
2.8 In-System Programming.........................................................................2-20
2.10 Test Points..............................................................................................2-23
2.11 Configuration Pads .................................................................................2-24
2.12 Solder Pads ............................................................................................2-25
Section 3
Troubleshooting Guide.......................................................................3-26
Section 4
Technical Specifications................... ......... .......... ......... ......... .......... ...4-27
Section 5
Technical Support............................. ......... .......... ......... ......... .......... ...5-28
Section 6
Complete Schematics.......................................... ......... ......... .......... ...6-29
STK525 Hardware User Guide User Guide 1
7608A–AVR–04/06

1.1 Overview

Section 1

Introduction

Congratulation for acquiring the A VR® STK525 Starter Kit. This ki t is designed to give designers a quick start to develop code on the AT90USBxxx and for prototyping and testing of new designs.
This document describes the STK525 dedicated to the AT90USBxxx 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 complement the evaluation and enable additional development capability, the STK525 can be plu gged into the Atmel STK500 Start er Kit Board in order to use the AT90USBxxx with advanced features such as variable VCC, variable VRef, variable XTAL, etc. and supports all AVR development tools.
To increase its demonstrative capabilities, this stand alone board has numerous on­board resources (USB, RS232, joystick, data-flash, microphone and temperature sensor).
This user guide acts as a general getting started guide as well as a comple te technical reference for advanced users.
STK525 Hardware User Guide 1-3
7608A–AVR–04/06
Introduction
Figure 1-1 . STK525 Board

1.2 STK525 Starter Kit Feature s

The STK525 provides the following features:
AT90USBxxx TQFP device (2.7V<Vcc<5.5V),
AVR Studio® software interface
USB software interface for Device Firmware Upgrade (DFU bootloader)
STK500 compatible
Power supply flagged by “VCC-ON” LED:
– regulated 3 or 5V, – from an external power connector, – from the USB interface (USB device bus powered application), – from STK5 0 0
ISP connector for on-chip ISP,
JT AG connector:
– for on-chip ISP, – for on-chip debugging using JTAG ICE,
Serial interfaces:
– 1 USB full/low speed device/host interface – RS-232C ports with RTS/CTS handshake lines,
On-board resources:
– 4+1-ways joystick, –4 LEDs, – temperature sensor, – microphone, – serial dataflash memory,
(2)
(1)
,
(2)
,
1-4 STK525 Hardware User Guide
7608A–AVR–04/06
Introduction
On-board RESET button,
On-board HWB button for force bootloader section execution at reset.
System clock:
– external clock from STK500 expand connectors – 8 MHz crystal,
Numerous access points for test.
Notes: 1. The STK525 is suppor ted by A VR S tudi o®, ver sion 4.12SP2 or higher . For up-to-date
information on this and other AVR tool products, please consult our web site. The newest 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 latest version of Flip and the DFU bootloader Hex file if needed.
STK525 Hardware User Guide 1-5
7608A–AVR–04/06

2.1 Overview

Section 2

Using the STK525

This chapter describes the board and all its features.
Figure 2-1 . STK525 Overview
USB MiniAB RS232 JTAG ISP External Power
C Sensor
Pin1
STK500 Expand0
TQFP64 Socket
LEDS
Microphone
Vbus Gen. Setting
Joystick Potentiometer ResetCrystal
Vcc Src. Setting
Data Flash
STK500 Expand1
Bootloader Activation
STK525 Hardware User Guide 2-6
7608A–AVR–04/06

2.2 Power Supply

2.2.1 Power Supply Sources
Using the STK525
The on-board power supply circuitry allows various power supply configurations.
The power supply source can come from three different
USB connector,
JACK PWR connector (J6, See Figure 2-2),
STK500
USB powered: When used as a USB devi ce bus powered application, the STK525 can be powered via
the USB VBUS power supply line.
JACK PWR connector: – Need of a male JACK outlet,
– Input supply from 9 up to 15V – No specific polarization
(2)
is required.
Figure 2-2 . JACK PWR Connector (J6)
(1)
DC,
(3)
and exclusive sources:
Figure 2-3 . M ale JACK Outlet and Wires
+
-
STK500 Powered: (c.f.
STK525 Hardware User Guide 2-7
“STK500 Resour ces” on page 19).
Notes: 1. 15V is the maxim um level limitation of an unidirectional transit diode.
2. There is a diode (bridge) voltage level between the negative output of the power supply and the STK525 “GND”. This could introduce some gap of voltage during measurement and instrumentation.
3. Caution: Do not mount more than one power supply sour ce on STK525.
7608A–AVR–04/06
Using the STK525
2.2.2 Pow er S upp l y Sett in g
Vcc Source
Jumper position
VBUS 5
REG 5 5V
Table 2-1 . Power Supply
VCC power
supply value
This is the default confi guration. This should be used for a typical USB
VBUS
(4,7V to 5. 0V)
device “bus powered” application. In this mod e, the STK525 is powered
directly from th e USB bus, and no other external power supply is required.
This configuration can be used for a USB “self powered” device application” or when operating has a USB host.
To use this conf iguration an exter nal power supply must be connected to J6 connector.
(1)
Setting
Comments View
Source
Reg 5
Reg 3.3
VBUS 5
STK
Source
Reg 5
Reg 3.3
VBUS 5
STK
VCC
VCC
REG 3.3 3.3V
Depends on
STK
STK500 VTG
setting
Notes: 1. Caution: The STK500 has its own “ON/OFF” switch
This configuration allows the STK525 to be used in a 3V range applicat ion.
This configuration can be used with both device or host mode USB applications.
To use this conf iguration an exter nal power supply must be connected to J6 connector.
This configuration allows the STK525 to be used with an STK500 board.
In this mode, the STK525 power supply is generat ed and configured accord i ng to th e “VT G ” par ameter of the STK500 (1).
VCC
Source
Reg 5
Reg 3.3
VBUS 5
STK
VCC
Source
Reg 5
Reg 3.3
VBUS 5
STK
2-8 STK525 Hardware User Guide
7608A–AVR–04/06
2.2.3 VBUS Generator Setting
Using the STK525
When using the A T90USBxxx microcontroller in USB ho st mode. The STK5 25 should provide a 5V power supply over the VBUS pin of its USB mini AB connector.
A couple of transistors on the STK525 allows the UVCON pin of the AT90USBxxx to control the VBUS gene ration (See Figure 2 -4). In this mode the S TK525 is powe red by external power supply source (J6 or STK500 expand0/1 connectors). JP7 allows to select the 5V source used by the VBUS generator.
Figure 2-4 . VBUS generator schematic
JP7
VTG
STK
Ext
UVCON
1 3
VBUS ge n
R33
100k
2
R32 10k
Q2 BC847B
FDV304P/FAI
M1
VBUS
C34
4.7uF
-
Table 2-2 . VBUS Generator Setting
“Vbus Gen”
Jumper position
“Ext” Ext e rnal po w er su pp ly from J6
“Stk”
STK525 power supply Comments View
Exte r n a l po w er su pp ly from Expand0/1 (connected to a STK500)
This is the default configuration. The VBUS generator source is the
on-board 5V regulator.
The VBUS generator source is the STK500.
Note: The “Vtarget” setting of STK500
should be set to “5V”.
Ext
Ext
Vbus
Gen
Stk
Vbus
Gen
Stk
STK525 Hardware User Guide 2-9
7608A–AVR–04/06
Using the STK525
2.2.4 “POWER-ON“ LED

2.3 RESET

The POWER-ON LED is always lit when power is applied to STK525 regardless of power supply source and the regulation.
Figure 2-5 . “VCC-ON” LED
Although the AT90USBxxx has its on-chip RESET circuitry (c.f. AT90USBxxx Datasheet, section “System Control and Reset), the STK525 provides the AT90USBxxx a RESET signal which can come from 3 different sources:
2.3.1 Power-on RESET
2.3.2 RESET Push Button
The on-board RC network acts as power-on RESET.
By pressing the RESET push button on the STK525, a warm RESET of the AT90USBxxx is performed.
Figure 2-6 . RESET Push Button (RST) Implementation
2-10 STK525 Hardware User Guide
7608A–AVR–04/06
2.3.3 STK500 RESET
(c.f.
“RESET from STK500” on page 20)

2.4 AT90USBxxx AVR Microcontroller

2.4.1 Main Clock XTAL
To use the USB i nterface of the AT90USBxxx, the clock source should always be a crystal or external clock oscillator (the internal 8 MHz RC oscillator cannot be used to operate with the USB interface). Only the following crystal frequency allows proper USB operations: 2MHz, 4MHz, 6MHz, 8MHz, 12MHz, 16MHz. The STK525 comes with a default 8MHz crystal oscillator.
When closing ST KX1 and STKX2 s witches, and STK525 is connected to an STK500, the STK525 can operate with the “STK500 Osc” frequency parameter.
2.4.2 Anal og P ower Supply
Using the STK525
ANA REF By default, AREF is an output of AT90USBxxx.

2.5 Serial Links

2.5.1 USB
AVCC By default, AVCC is equivalent to VCC.
An external AREF source can be chosen (c.f.
The STK525 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 2-7 . USB mini A-B Receptacle
“STK500 Resour ces” on page 19).
When connected to a m ini B plug, the AT90USBxxx opera tes as an “USB device” (the ID pin of the plug is unconnected) and when connected to a mini A plug, the AT90USBxxx operates as a “USB host” (the ID pin of the plug is tied to ground).
STK525 Hardware User Guide 2-11
7608A–AVR–04/06
Using the STK525
2.5.2 RS-232C
The AT90USBxxx is a microcontroller with an on-chip USART peripheral (USART1). Only the asynchronous mode is supported by the STK525.
The STK525 is supplied with a RS-232 driver/receiver. One female DB9 connector assumes the RS-232 connections.
Figure 2-8 . RS -232 DB9 Connector
Figure 2-9 . RS -232 DB9 Connections
RS-232 D B 9 fron t view
5
1
234
69
78
Figure 2-10 . Typical PC Connection Layout
STK525 / RS-232 DB9
Function Pin No Function
RTS (
AT90USBxxx
Pin No
2TxD (AT90USBxxx)
5GND
If Hardware Data Flow Control
7CTS (AT90USBxxx) 7
)
pin 2
RS-TxD
pin 3 RS-RxD pin 4
pin 6 pin 5 GND pin 7 RS-CTS
pin 8 RS-RTS
PC / DB9 serial port
(COM1 o r C OM x )
2 3
RxD (PC) TxD (PC)3RxD (AT90USBxx x)
5 GND
RTS (PC)
8
CTS (PC)8
2-12 STK525 Hardware User Guide
7608A–AVR–04/06
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