Atmel ATAVRBFLY Data Sheet

4271C–AVR–04/05

More information about the STK500 can be found in the STK500 User Guide, 
which is available at the Atmel web site, 

www.atmel.com

. See the STK500 User 

Guide for information on how to use the STK500 front-end software in High-volt-
age Programming mode. 

Figure 3-8 shows how to connect the JTAG ICE probe to the AVR Butterfly. 

Figure 3-8.  JTAG connector

The JTAG connector must be mounted on the back-side of the AVR Butterfly.

The JTAG connector is used for the ATmega169 built in JTAG interface. The pinout of
the connector is shown in Figure 3-9 and is compliant with the pin out of the JTAG ICE
available from Atmel. Connecting a JTAG ICE to this connector allows On-chip Debug-
ging of the ATmega169. 

More information about the JTAG ICE and the On-chip Debugging can be found in the
AVR JTAG ICE User Guide, which is available at the Atmel web site, 

www.atmel.com

. 

Pin 7, NC(VCC) is the Vsupply pin for the JTAG. This pin is not connected 
because the JTAG would draw power from the battery on the AVR Butterfly. 

Pin 8, NC(BS2) and the pin 10, GND(XTAL1) can be modified serve as the BS2 and
XTAL1 pin during High-voltage Parallel Programming. For more details see 3.2.2 High-
voltage Parallel Programming.

Figure 3-9.  JTAG Connector

It is highly recommended to apply external power (3,1 – 4,5V), when using the 
JTAG to save the battery. See Figure 3-10 for how to connect external power. 

JTAG

1   2

TCK

GND

TDO

TMS

VCC

RST

NC(VCC)

NC(BS2)

GND(XTAL1)

TDI