Description of User Switches

The Switches connected to the debug headers are implemented as shown in the figure below.

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.

Note:
In the AVR you 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 560R resistor is to limit the current going into the AVR.

See Also

• STK500 Starter Kit User's Guide
• Description of User_LEDs
• Connection of LEDs and Switches
• Port Connectors
• Description of User RS232 Interface
• Description of Dataflash Pins
• Target Socket Section
• ISP Programming
• High Voltage Programming
• Parallell High Voltage Programming
• Serial High Voltage Programming
• Jumper Settings
• Target VCC Settings, TVCC
• Analog Reference Voltage, AREF
• Reset Settings, RESET
• Clock Settings, XTAL1 and OSCSEL
• BSEL2 Jumper
• Expansion Connectors
• Prog Ctrl and Prog Data Headers
• Misc