ATmega32A pins output issues

Question

I’ve an issue with my ATmega32A in some of PORTC pins.

I’m trying to control some LEDs using MCU but I faced an issue with PINC2,3,4,5 as shown in picture bellow.

Off state (LED num 3,4,5,6 from the bottom):

On state:

My code:

And here is my schematic:

I measured the output voltage in those pins using voltmeter.

With LEDs connected:

• On state: 2.6 V
• Off state: 2.9 V

Without the LEDs:

• On state: 4 V
• Off state: 5 V

Only one pin PINC4:

• With LEDs connected: 1 V
• Without the LEDs: 2 V

I don’t know what’s going on. Can anyone explain what’s happening?

Answer 1

By default, on these pins on PORTC the JTAG interface is enabled. So, to get access to PORTC you need to disable the JTAG interface by setting the Fuse High Byte to 0xD9.

How can I disable the jtag in atmega 32 using serial programmer?

Or try to use this code to disable JTAG in your software:

/*disable JTAG*/
MCUCSR |= (1 << JTD); 
MCUCSR |= (1 << JTD);

Reference: ATmega32A Data Sheet