Getting Started

2-4 AVR STK500 User Guide

1925C–AVR–3/03

Figure 2-3. AVR Studio STK500 Programming Menu

Complete descriptions of using the STK500 interface in AVR Studio are given in Section

5 on page 5-1.

AVR STK500 User Guide 3-1

Rev. 1925C–AVR–3/03

Section 3

Hardware Description

Figure 3-1. STK500 Components

3.1 Description of

User LEDs

The STK500 starter kit includes 8 yellow LEDs and 8 push-button switches. The LEDs

and switches are connected to debug headers that are separated from the rest of the

board. They can be connected to the AVR devices with the supplied 10-wire cable to the

pin header of the AVR I/O ports. Figure 3-4 shows how the LEDs and switches can be

connected to the I/O port headers. The cables should be connected directly from the

port header to the LED or switch header. The cable should not be twisted. A red wire on

the cable indicates pin 1. Confirm that this is connected to pin 1 on each of the headers.

Figure 3-2 shows how the LED control is implemented. This solution will give the same

amount of light from the LED for all target voltages from 1.8V to 6.0V.

Power Switch

Power Connector

Power LED

Parallel Programming

Headers

RS-232 Port

for Programming

Master MCU

Status LED

RS-232 Port

for Communication

Options Setting

Jumpers

Sockets for

Target AVR

Headers

for I/O Ports

Switches

Header for

Switches

RS-232 Interface

Header

DataFlash Interface

Header

LEDs

Header for

Expansion Boards

Header for LEDs

10-pin ISP Header

(for External Target Only)

6-pin ISP Header

Target ISP Headers

Program Button

Socket for

Crystal

Target Reset

Push Button

Header for

Expansion Boards

Hardware Description

3-2 AVR STK500 User Guide

1925C–AVR–3/03

Figure 3-2. Implementation of LEDs and LED Headers

Note: The AVR can source or sink enough current to drive a LED directly. In the

STK500 design, a transistor with two resistors is used to give the same amount

of light from the LED, whatever the target voltage (VTG) may be and to turn off

the LEDs when VTG is missing.

3.2 Description of

User Switches

The switches connected to the debug headers are implemented as shown in Figure 3-3.

Pushing a switch causes the corresponding SWx to be pulled low, while releasing it will

result in VTG on the appropriate switch header connector. Valid target voltage range is

1.8V < VTG < 6.0V.

Figure 3-3. Implementation of Switches and Switch Headers

Note: In the AVR, the user can enable internal pull-ups on the input pins, removing the

need for an external pull-up on the push-button. In the STK500 design, we have

added an external 10K pull-up to give all users a logical “1” on SWn when the

push-button is not pressed. The 150R resistor limits the current going into the

AVR.

LED1

LED3

LED5

LED7

VTG

LED0

LED2

LED4

LED6

GND

1 2

LEDn

10K

VTG

+5V

150R

10K

150R

VTG

SW1

SW3

SW5

SW7

VTG

SW0

SW2

SW4

SW6

GND

1 2

Part #	C1925
Description	BLOCK, JUNCTION - Bulk
Category	HARDWARE
Availability	In Stock
Qty	2

C1925

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