ATmega 16 problem PC2 to PC5 always high

ATmega 16 problem PC2 to PC5 always high

I have about 5 atmega 16 microcontrollers with PC2 to PC5 pins are always high even if i programmed them as outputs and make PORTC=0x00.this problem occurs when the JTAG interface is enabled in ATmega 16.

To get rid from this problem you have to disable the JTAG.

Here I disablled the JTAG interface using the avr studio and STK500 board.

Steps :

1- Connect the STK500 board through usb .
2- Press on the connect icon as shown in the following picture :

3- Select the STK500 board and auto in the port as shown :

4-  Be sure that atmega 16 microcontroller is selected in the main tab

5- In the fuses tab disable the JTAG interface by unchecking the JTAGEN fuse and the press program at the bottom as shown in the figure :