sending char from microcontroller to another one

[foxbrain]

hi
how can i send a char array from atmega168 to atmega16?
do i need a protocol?
is there a ready c function for it?
i'm using avr studio 5.1
thanks

 

[HMS1021]

With this device you have 4 choices including SPI, I2C, 8 GPIOs, or the UART. If both are on the same board (or mounted in the same case) I would look at SPI first but it really depends on the application. If you can spare the 8 GPIOs on each device and assuming the devices are on the same PCB that may be the best approach. If it is two separate cases with a cable between then the UART only way to go. There is example code for each of these interfaces that would do the job.

 

[Briez]

I think UART is the best and easier option than any other protocols....

Go for UART programming.

 

[tpetar]

USART Communication in AVR microcontrollers
https://introbots.wordpress.com/2013/01/30/usart-communication-3/

Serial communication (Data receive) using AVR Microcontroller (ATmega16) USART
**broken link removed**




Best regards,
Peter

:wink:

 

[Raady Here]

Use SPI,

you can use inbuilt functions which are developed by processor manufacturer already.
go check library functions first.

 

[HMS1021]

SPI is the best choice if the two devices are on the same board or the two boards are close to each other. Its only 4 wires and ground. It is fast at 6Mbps or so, and it is bidirectional.

 

[foxbrain]

i liked the usart so after i had understood it i wrote these codes :
the sender: atmega168

#define F_CPU 7372800 // Clock Speed
# define USART_BAUDRATE 9600
# define BAUD_PRESCALE (((F_CPU / (USART_BAUDRATE * 16UL))) - 1)
void init_usart(void)
{
	UCSRB |= (1 << RXEN) | (1 << TXEN); // Turn on the transmission and reception circuitry
	UCSRC |= (1 << URSEL) | (1 << UCSZ0) | (1 << UCSZ1); // Use 8- bit character sizes
	UBRRH = (BAUD_PRESCALE >> 8); // Load upper 8- bits of the baud rate value into the high byte of the UBRR register
	UBRRL = BAUD_PRESCALE; // Load lower 8- bits of the baud rate value into the low byte of the UBRR register
}
void main()
{
init_usart();
char number[26];
while ((UCSRA & (1 << UDRE)) == 0) {}; // Do nothing until UDR is ready for more data to be written to it
UDR = number; // Echo back the received byte back to the computer
while ((UCSRA & (1 << UDRE)) == 0) {};
}

the receiver: atmega16A

# include <avr/io.h>
# define USART_BAUDRATE 9600
# define BAUD_PRESCALE (((F_CPU / (USART_BAUDRATE * 16UL))) - 1)
void init_usart(void)
{
	UCSRB |= (1 << RXEN) | (1 << TXEN); // Turn on the transmission and reception circuitry
	UCSRC |= (1 << URSEL) | (1 << UCSZ0) | (1 << UCSZ1); // Use 8- bit character sizes
	UBRRH = (BAUD_PRESCALE >> 8); // Load upper 8- bits of the baud rate value into the high byte of the UBRR register
	UBRRL = BAUD_PRESCALE; // Load lower 8- bits of the baud rate value into the low byte of the UBRR register
}
int main ( void )
{
	DDRC=0xFF;
	char rec;
	init_usart();
	for (;;) // Loop forever
	{
		while ((UCSRA & (1 << RXC)) == 0) {}; // Do nothing until data have been received and is ready to be read from UDR
		rec= UDR; // Fetch the received byte value into the variable " ByteReceived "
		if(rec[0]==3){do something}
	}
	return(0);
}

will this code works???
do i get at the receiver the same array char number[26] ?

 

[foxbrain]

i'm getting an error here:

UDR = number;

since number is an array of char and UDR must be uint8_t.
so how can i transfer this array of char ?

 

[Briez]

Try to send your array of characters by looping into UDR and by same technique try to receive that array into buffer array of same size.

 

[jayanth.devarayanadurga]

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Code C - [expand]
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for(i = 0; i == arraylength; i++){
             UDR = number[i];
}

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