ATMEGA32 PORTC problem

[ANS HAFEEZ]

Salam
i am using portC of atmega32 as a input port and connect PORTC with pulldown resistor but getting problem on PC4 and PC3
my programm is perfect simulation is perfect but when input comes from PC4 and PC3 pin i get No out put

getting similer problem on output PC2 and PC3 pins consistently on 1.79V even if there is logic 1 or 0

Any solution

 

[alexan_e]

We need a schematic and the relevant part of the code that relates with the port I/O

 

[ANS HAFEEZ]

ok ok i got one that i should disbale JTAG for the proper I/O operation
but how to disable it
i disbale it from fus bits in ponyprog but got the same problem

So How to disable it FROM PROGRAMMING

ch=usart_getchar();
		if (ch==48)
		{
			PORTC=0b00001111;
			PORTA=0b00011111;
		}
		else if (ch == 49)
		{
			PORTC=0b00000001;			//FOR ONE 
			PORTA=0b00010111;
		}
		else if (ch == 50)
		{
			PORTC=0b00000010;			//FOR TWO
			PORTA=0b00011011;
		}
		else if (ch == 51)
		{
			PORTC=0b00000011;			//FOR THREE
			PORTA=0b00011101;
		}
		else if (ch == 52)
		{
			PORTC=0b00000100;			//FOR FOUR
			PORTA=0b00011110;
		}
		else if ( ch == 53)
		{
			PORTC=0b00000101;			//FOR FIVE
			PORTA=0b00001111;
		}

 

[alexan_e]

Here is the relevant part of the datasheet

JTAG Interface and On-chip Debug System

There are three alternative ways to disable On-chip debug

•Disable OCDEN Fuse.
•Disable JTAGEN Fuse.
•Write one to the JTD bit in MCUCSR.

and

• MCUCSR Bit 7 – JTD: JTAG Interface Disable

When this bit is zero, the JTAG interface is enabled if the JTAGEN Fuse is programmed. If this
bit is one, the JTAG interface is disabled. In order to avoid unintentional disabling or enabling of
the JTAG interface, a timed sequence must be followed when changing this bit: The application
software must write this bit to the desired value twice within four cycles to change its value.

So you need to use

MCUCSR |=(1<<JTD);
MCUCSR |=(1<<JTD);

and it's best to disable interrupts while executing these two lines to make sure they are not interrupted.