sim300cz and atmega16L

Great.. we are all happy for you

Don´t be!!!
What I was trying to do was to have the same error repeated on the breadboard.
If the error could be repeated, then I would check what part of the PCB was wrong.
But, I couldn't repeat the error, even though I made all the electrical arrangements according to my schematic, the one that originated the PCB (using Altium).
So, I still don't have it working...:-(
..and still need help....

Well in my book having a working example is a good thing.
Compare the signals/levels on the working board to the faulty one.
Try to be positive

Thanks for your words, ExperimenterUK.
After a week on top of something that does't work, and you still have no idea of where to go, your words are the best that occured to me this week.
Interesting is that I have a PCB, factory made. I set up 5 of them, with the same error.
So, I figured out that something on my PCB was strangely wrong.
Got a breadboard, got the HD datasheet and started all over. Checking schematics, checking power consumption... all possible (and impossible) things. Soldered wires to the module, made a big spider, and worked ok.
Everything ok.
Soldered just the module on the PCB, got some wires out of the corresponding pins on different parts of the PCB, and no error.
Got the whole PCB as one, and the error was there.
I'm trying a firmware solution that I'm sure will solve the problem.
I'll let you know.
Thanx again!

Thanks for your words, ExperimenterUK.
After a week on top of something that does't work, and you still have no idea of where to go, your words are the best that occured to me this week.

luizsalomon

Thanks for the comment,nice to know I helped

@luizsalomon: say big thanks to him, press that thanks button

hey when you finally connect the SIM to the ATmega do i have to convert the TX RX with something because i got one week trying to send a text messange and it not working i dont know if its the connection or i have to convert something can you help me in that plis???

I have the exact same problem. I also try to interface between atmega16 and telit module(with evaluation board). uC work well when I connect with hyper terminal. Module work well when i connect with hyper terminal. But when I connect both there is no response. I also did the LED trick. Then I found it didnt work from the first. That mean it didnt response the AT (which is send by mcu). Is there any connection problem? I used max232 and RTS of telit's module is connect with max232, which is constant "1" (i.e positive voltage). Help me someone. Here is the code:

#include <avr/io.h>
#include <avr/interrupt.h>

unsigned int rx_ack, x=0;
static unsigned char rx_buffer[25];
unsigned char flag;

int usart_putchar( unsigned char data );

ISR(USART_RXC_vect)
{
while ( !(UCSRA & (1<<RXC)) ) ;
rx_buffer[x] = UDR;

if((rx_buffer[x] == 'K') && (flag ==1))
{
x=0;
flag=0;
rx_ack = 1;
}


if(rx_buffer[x] == 'O')
{
x++;
flag=1;
}

}


int main()
{
unsigned int i, ii;

DDRA = 0xFF;
UBRRH = 0x00; //Setting baudrate
UBRRL = 0x0C; //Setting baudrate

UCSRA = ( 1 << U2X ); //Double the speed
UCSRB = ( 1 << RXEN ) | ( 1 << TXEN )| (1<<RXCIE); //Enable rx and tx
UCSRC = ( 1 << URSEL ) | ( 1 << UCSZ1 ) | ( 1 << UCSZ0 ); //8 data bit
sei();


while(1)
{
for(i=0; i<65535; i++)
{
;
}
usart_putchar('A');

for(i=0; i<65535; i++)
{
;
}
usart_putchar('T');

for(i=0; i<65535; i++)
{
;
}
usart_putchar('\r');

for(i=0; ( rx_ack == 0 ) && ( i < 65535 ); i++)
{
for(ii=0; ii<10; ii++)
{
;
}
}

if(rx_ack == 1)
{
rx_ack = 0;
rx_buffer[0] = rx_buffer[1] = rx_buffer[2] = 0x00;

PORTA |= (1<<PA0);
for(i=0; i<65535; i++)
{
;
}
PORTA &= ~(1<<PA0);
}

}

return 0;
}




int usart_putchar( unsigned char data )
{

unsigned int i;

for( i = 0; !( UCSRA & ( 1 << UDRE ) ); i++ ) // Wait for empty transmit buffer
{
;
}

UDR = data; // Start transmittion

return 0; //Cast and return int value
}

@ williamrdg and @ williamrdg
normally there is no tricky connections
just connect rx of controller to tx of modem
connect tx of controller to rx of modem
ground connect to ground
if modem voltage is 3.3 v then u has to drive controller at 3.3 volt or
use a voltage divider to convert controller 52 volt logic to 3.3 volt

VOILA!!!!!!!!!!!!! Its working!!!!! Thanx.