15

Troubleshooting Guide

Programming problems

Problem

Cause

Solution

ISP programming

does not work

ISP cable is not connected Connect a 6-pin cable between the ISP6PIN

connector on STK500 and the ISP connector on

STK503. See also Programming the AVR.

ISP programming

does not work

The ISP clock is to fast if

the AVR is running at a low

clock frequency.

Make sure the clock switch on STK503 is in the

right position. In the Board page of the

programming dialog in AVR Studio, try reducing

the ISP clock frequency.

High-Voltage

programming does

not work.

The 10-pin cables are not

connected correctly.

See the Programming the AVR chapter for

setup.

High-Voltage

programming does

not work.

The BSEL2, OSCSEL,

RESET and VTARGET

jumpers on STK500 are not

set right.

See the Programming the AVR chapter for

setup.

High-Voltage

programming does

not work.

The STK504 clock switch is

in the wrong position.

Set the switch to the STK500 position. See also

Programming the AVR.

General problems

Problem

Cause

Solution

Some of the port pins are

not working .

The AVR is not

properly mounted in

the ZIF socket.

Make sure the chip is properly aligned in the

socket. When the spring-loaded latch is

depressed, the chip should fit nicely into the

bottom of the socket.

The code isn't running.

The AVR has

no/wrong clock

source.

According to the clock fuse setting, select the

appropriate clock source on STK500 and

STK503. Check the OSCSEL jumper on

STK500 and clock switch on STK503. If you are

using a crystal in one of the sockets, check that

it is firmly mounted in its socket.

The AVR will not run on x

MHz, but works ok on

lower frequencies.

The clock frequency

is exceeding the

clock rate of the AVR

(at a certain

operating voltage).

Check that you are running the AVR within

specifications. Check the speed grade of the

AVR and consult the datasheet for operating

frequencies and voltages.

The AVR will not run on x

MHz, but works ok on

lower frequencies. I have

a x MHz crystal mounted

on STK500

Crystals should be

placed in the crystal

socket on STK503.

Place the crystal in the socket on STK503. Set

the clock switch to the position closest to the

crystal socket..