Function

Update SPI flags and packet length and check whether SPI is busy

Purpose

Provide application program with information about current SPI status

Syntax

bit getStatusSPI()

Parameters

  –

Return value

•     1 – SPI busy

•     0 – SPI not busy

Output values

•     SPIpacketLength: received packet length

•     param2.3 (_SPIRX): 1 – Something received on SPI.

•     param2.4 (_SPICRCok):  1 – The last received SPI CRCM was O.K.

Preconditions

SPI must be enabled by enableSPI

Remarks

•     Output values (param2) have a different format than the SPI status sent to the Master.

•     See IQRF SPI Technical guide and Example E07-SPI.

Side effects

  –

See also

enableSPI, disableSPI, startSPI, stopSPI, restartSPI

Example 1

     // Master  ->  Slave 

  enableSPI();              // Master is allowed to transmit from now

Receive:

  clrwdt();

  if (getStatusSPI())       // Wait until SPI is not busy

    goto Receive;

  if (_SPIRX)               // Anything received?

  {                         // Yes:

    if (!_SPICRCok)         //   CRCM matched?

    {                       //   No:

      startSPI(0);          //     Restart SPI

      goto Receive;         //     and try to receive again.

    }

                             //  Yes:

                             //    BufferCOM is automatically protected now

                             //    not to be overwritten by next SPI packet.

                             //    Thus, stopSPI is not necessary here.

                             //    Packet length is in SPIpacketLength.

    copyBufferCOM2INFO();   //    Store received packet

    startSPI(0);            //    and then allow Master to transmit again.

  }

  else

    goto Receive;           // Nothing received yet

// ...                         Continue here after successful receiving

  waitMS(1);                // Time for finishing startSPI(0) on background

  disableSPI();              // otherwise Master's CRCS check fails.

                             // The delay depends on the Master application.

Example 2

enableSPI();

startSPI(2);                 // 2 B to send to master

while (getStatusSPI())      // Wait until SPI is not busy

  waitMS(1);

...                          // Now the transfer is finished