CCS/TMS570LS3137: Mibspi communication ,when to start

hello 

 and  when send data in slave?

Hello 

  I see some paper，that  says mibspiTransfer ,this function send data .is it right?

  but,in my slave  I also use mibspitranfer function,that send data.

  slave dont have clock,master give its clock,why use this function? 

Hello,

In SPI, only Master generates the clock signal (SPICLK). There is always only one master, but there can be multiple slaves.

When data is sent from the master to a slave, it's sent on SIMO data line (Master Out / Slave In). If the slave needs to send a response back to the master, the master will continue to generate a prearranged number of clock cycles, and the slave will put the data onto SOMI data line (Master In / Slave Out). Because the master always generates the clock signal, it must know in advance when a slave needs to return data and how much data will be returned. 

Yes, the mibspiTransfer() can be used to transmit data in both master and slave sides. 

Before master generates the SPICLK, the slave has to copy the data to mibspi RAM (multi-buffered mode) or spiDat1 register first.

Thank you

  Now  I use mibspi communication  two cpu  with master and slave.

  question：1. In slave this funciont "while(mibspiIsTransferComplete()==flase);"whether still wait for the master send data,if that the salve can continue execute next code.  ？？

Hi,

The INTFLGRDY bit in TGINTFLG register is set when this transfer group has been transferred. But the MibSPI interrupt service routine (ISR) reads the INTVEC0/1 register to check the pending interrupt. Reading those interrupt vector registers will clear the interrupt flag in TGINTFLG register. 

If you check while(mibspiIsTransferComplete()==flase) inside the MibSPI notification or after, the while() will run forever since the return value is False.

When INTFLGRDY is set, the slave TG has been transferred, and the master stops generating clock.