10

6.

Start AVR Studio. On the Tools menu, select "Program AVR/ Connect..."

You are now ready to program the device. For more information on how to use

the programming dialog, see the Frontend software section in the STK500 user

guide.

STK503 Clock Sources

The ATmega2560 and its like have two clock inputs; XTAL and TOSC. Two

switches on the STK503 selects what is connected to these two inputs.

Figure 5-1: The clock selection switches XTAL and TOSC

The XTAL switch

A clock source connected to the XTAL clock input is used to drive the internal

chip clock. The source can be a crystal, a resonator or an external clock signal.

The XTAL switch sitting on STK503 selects what is connected to the XTAL pins.

STK500 can supply two different clock signals:

•

STK500 can generate a software controlled signal with a maximum

frequency of 3.69MHz

•

A crystal can be placed in the crystal socket.

You select between these two sources with the OSCSEL jumper. This signal is

available on STK503.

The STK503 also has a socket for a crystal. This socket should be used instead

of the one on STK500, at least for high-frequency crystals (>8MHz).

The XTAL switch selects what signal is routed to the XTAL pin on the AVR:

•

The STK500 supplied clock (set the switch to the position indicated by the

text STK500)

•

The crystal socket on STK503 (set the switch to the position nearest the

crystal socket)