How to send a string in API mode?

Question

Hi all!

I have my network coordinator configured in API mode and I am sending and receiving sensor data from a network of router and end devices in AT mode.

I want to now send string messages to a particular router device that is connected to a microcontroller (an arduino). What frame type should be used for sending string data? And is there any resources regarding working in API mode and the different frame types available? From the list of frame types available in XCTU it is not obvious to me which frame type I should use.

Any help on this would be greatly appreciated.

Answer 1

I use the Transmit Request frame (0x10). A real life Arduino example that I constructed recently includes the following code snippet:

static uint8_t frame_id = 1;
uint8_t xbee_frame[ 17 + 9 + 1];
int pos = 0;

/* Compose the frame header for a transmit request (0x10). */
xbee_frame[ pos++ ] = 0x7e;
xbee_frame[ pos++ ] = ( ( sizeof( xbee_frame ) - 4 ) >> 8 ) & 0x00ff;
xbee_frame[ pos++ ] = ( sizeof( xbee_frame ) - 4 ) & 0x00ff;
xbee_frame[ pos++ ] = 0x10;
/* Setup destination address and transmit options. */
xbee_frame[ pos++ ] = frame_id++;
if( frame_id == 0 )
{
frame_id = 1;
}
for ( int i = 0; i < 8; i++ )
{
xbee_frame[ pos++ ] = xbee_address_64[ i ];
}
xbee_frame[ pos++ ] = xbee_address_16[ 0 ];
xbee_frame[ pos++ ] = xbee_address_16[ 1 ];
/* Options: retry/repair enabled, encryption enabled, no extended timeout. */
xbee_frame[ pos++ ] = 0;
xbee_frame[ pos++ ] = 0x20;

/* Add payload. */
pos = pos + add_16_bits_to_payload( &xbee_frame[ pos ], temperature );
pos = pos + add_24_bits_to_payload( &xbee_frame[ pos ], pressure );
pos = pos + add_16_bits_to_payload( &xbee_frame[ pos ], soil_temperature );
pos = pos + add_8_bits_to_payload( &xbee_frame[ pos ], soil_humidity );
pos = pos + add_8_bits_to_payload( &xbee_frame[ pos ], water_barrel_indicators );

/* Compute the checksum. */
uint8_t checksum = 0x00;
for( int i = 3; i < sizeof( xbee_frame ) - 1; i++ )
{
checksum += xbee_frame[ i ];
}
checksum = 0xff - checksum;
xbee_frame[ pos ] = checksum;

/* Copy the frame to the XBee. */
XBEE_SERIAL_PORT.write( xbee_frame, sizeof( xbee_frame ) );

Comments

Ocwo92 is correct.  Your reseorce information would be found in the API section of the product manual for the XBee module.

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hello, could you explain me how do you assign the position and value to each byte of the RF data in / * Add payload. */ ...please

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That to me would be something you need to talk to your Arduino support about. After all, it is the code you are writing to run on that device that you need help with.

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I just don't understand how do you add the payload in the frame for data that is changing. Anyway thanks