Basic Transmission

In order to transmit data using an AFDX COM Sampling port you must:

• Create the transmission virtual link using the mxfA664VlCreate() function.
• Create the sampling port using the mxfA664PortCreate() function.
• The messages to be sent must be stored in a MXF_A664_DATAREC structure.
• Start transmission using the mxfA664TxPeriodicUpdateMsgWrite() function with the port handle. No timing option is available, the transmission timing is controlled by the VL BAG scheduler.

Sampling default option is to only transmit when new data is written to the port buffer. MXF_A664_PORT_SAMPLING_OPT_SEND_STALE_DATA allows to continuously send data even if new data is not available, the current data will continue to be transmitted at the specified rate.

Example

ar664_sampling.c
The code snippets below demonstrate the basic steps needed to setup a Sampling COM port transmission.

// Create the transmission (TX) virtual link
if (!rc)
{
   memset(&vlParam, 0, sizeof(MXF_A664_VL_PARAM));
   vlParam.direction = MXF_A664_VL_DIR_TX;
   vlParam.VLId = vlid;
   vlParam.frameType = MXF_A664_FRAME_TYPE_ARINC664;
   vlParam.frameSizeMax = 512;
   vlParam.dir.Tx.subVlNumber = 1;
   vlParam.dir.Tx.bag = 1 * 1000 * 1000;  // 1ms
   vlParam.dir.Tx.netSelection = MXF_A664_NETSELECT_ALL;
   vlParam.dir.Tx.Ede.enable = FALSE;
   vlParam.dir.Tx.subVl[0].bufferSize = vlParam.frameSizeMax;
   vlParam.dir.Tx.subVl[0].maxBuffers = maxTxRecords;

   rc = mxfA664VlCreate(phyChn, &vlParam, &vlTx);
}

// Create the transmission COM port
if (!rc)
{
   inet_pton(AF_INET, DST_IP_ADRS, &srcIpAdrs);
   inet_pton(AF_INET, SRC_IP_ADRS, &dstIpAdrs);

   memset(&portParam, 0, sizeof(MXF_A664_PORT_PARAM));
   portParam.portType = MXF_A664_PORT_TYPE_COM;
   portParam.family = MXF_A664_PORT_FAMILY_IPV4;
   portParam.mode = MXF_A664_PORT_MODE_SAMPLING;
   portParam.dir.Tx.Sampling.rate = 10 * 1000 * 1000; // 10ms
   // This option allows to send the same data if no new data is available
   //portParam.dir.Tx.Sampling.options = MXF_A664_PORT_SAMPLING_OPT_SEND_STALE_DATA;
   portParam.type.COM.destAddress.port = DST_UDP_PORT;
   portParam.type.COM.destAddress.version.IPv4.address = ntohl(dstIpAdrs);
   portParam.type.COM.srcAddress.port = SRC_UDP_PORT;
   portParam.type.COM.srcAddress.version.IPv4.address = ntohl(srcIpAdrs);

   rc = mxfA664PortCreate(vlTx, &portParam, &portTx);
}

// Build the Transmit Record
memset(&txRec, 0, sizeof(txRec));
txRec.dataSize = TEST_DATASIZE;
txRec.repeatCount = 1;
for (dataIdx = 0; dataIdx < TEST_DATASIZE; dataIdx++)
   txRec.data[dataIdx] = (uint8)((dataIdx + ((count*TEST_DATASIZE) & 0xff)));
rc = mxfA664TxPeriodicUpdateMsgWrite(portTx, 1, &txRec);

...

if (!rc)
   rc = mxfA664PortRelease(portTx);

...