How to use SPI_MasterTransferBlocking and SPI_MasterTransfer properly?

[AhpKim]

Hi, 

I'm trying to use the SPI protocol between the IMU sensor, ASM330LHHX, and my MCU, MPC5748G.

How it's configured :

CS PIN : SIUL2->GPDO[26]

By using SPI_MasterTransferBlocking, I can send and receive the sensor data.

But the problem is that I can only get the IMU sensor data, and other modules such as CAN protocol and UART protocol stop running.

So here're two questions I want to ask,

1. How to stop the SPI_MasterTransferBlocking function properly? This is how I use this function:

After the transfer, shouldn't it be finished and start running other modules? It seems to have all the usage of the process.

2. So I used SPI_MasterTransfer function, but when I raise CS and run the SPI_MasterTransfer function, SPI_MasterTransfer status keep giving me STATUS_BUSY. 

Green line is CS, Yellow line is the Clock. 

So CS turned low before the transfer finished. Is there a way to fix this situation?

Any help is welcome.

Thanks,

[PetrS · Accepted solution]

Hi,

1) yes, blocking function is waiting inside until all defined number of bytes are sent or timeout expires. But interrupts are still enabled so can be handled normally from other modules. A timeout for the transfer is in milliseconds. If the transfer takes longer than this amount of time, the transfer is aborted and a STATUS_TIMEOUT error returned.

2) if there was no transfer before or it was already finished then function should not return STATUS_BUSY, rather STATUS_SUCCESS. For non-blocking function you should test for end of transfer before it can be again called, for example by using DSPI_GetTransferStatus function. For example like below, to ensure transfer is finished and CS (if driven my SW) can be deasserted.

dspi_transfer_status_t status=DSPI_TRANSFER_OK;

SIUL2->GPDO[24]=0;
DSPI_MasterTransfer(SPI0_INSTANCE, master_send, master_receive, 2);
do
{
     DSPI_GetTransferStatus(SPI0_INSTANCE, &status);
}while(status==DSPI_IN_PROGRESS);
SIUL2->GPDO[24]=1;

BR, Petr 

[AhpKim]

Thanks!! It worked!!