TDA4VM: TDA4 - About the delay time after SPI transmission is completed

chun chu1

Part Number: TDA4VM

Dear experts:

I tried to imitate the ipc_spi_master/ipc_spi_slave sample code in mcusw.

For this example, as long as the SPI packet is sent once, the Osal_delay() function must be called to wait for timeout value to initiate next transfer. Allow some time for slave to compose the response.

This delay time will cause the transmission to be too slow during continuous transmission.

If I don’t need the slave to respond to any data, how can I modify it so that there is no delay time after the master transmits?

/* Wait for timeout value to initiate next transfer.
* Allow some time for slave to compose the response */
Osal_delay(testParams->timeOutValue);

over 4 years ago

0 Sunil Kumar M S over 4 years ago

TI__Genius 12360 points

Hi Chun,

May I know the application/usecase you trying to? You do not need slave application.

Regards,

Sunil Kumar M S

0 chun chu1 over 4 years ago in reply to Sunil Kumar M S

Intellectual 330 points

Hi Sunil,

I use MCU_MCSPI2 (Master) in the MCU domain(MCU1_0) to actively send data to MCSPI4 (Slave) in the Main domain(MCU2_1), and use MCSPI3(Master) in the Main domain(MCU2_1) to actively send data to MCU_MCSPI1(Slave) in the MCU domain(MCU1_0).

Because in my use case, both the MCU domain and the Main domain have the need to actively send data. The bandwidth should be at least 3M bps.

At present, the above two SPI channels have been opened, but the delay time after sending each SPI data packet causes the transmission speed to be too slow.

0 Sunil Kumar M S over 4 years ago in reply to chun chu1

TI__Genius 12360 points

Hi Chun,

So in your usecase does slave also needs to send data back to master or is it only receiving data from master?

Regards,

Sunil Kumar M S

0 chun chu1 over 4 years ago in reply to Sunil Kumar M S

Intellectual 330 points

Hi Sunil,

In my usecase, the slave only receives data from the master.

0 Sunil Kumar M S over 4 years ago in reply to chun chu1

TI__Genius 12360 points

Hi Chun,

Ok understood. Then can you just configure master SPI to TX only mode and remove that Osal_delay as it is not required in your case.

You need to update .txRxMode variable in below file to SPI_TX_RX_MODE_TX_ONLY instead of SPI_TX_RX_MODE_BOTH and rebuild application.

mcusw\mcuss_demos\mcal_config\Spi_Demo_Cfg\output\generated\soc\j721e\mcu1_0\src\Spi_PBcfg.c

Regards,

Sunil Kumar M S

0 chun chu1 over 4 years ago in reply to Sunil Kumar M S

Intellectual 330 points

Hi Sunil,

I tried to configure the master SPI to only TX mode, it can transmit normally, and the slave device can also receive data packets.

But when the Master continuously sends SPI packets, after deleting the Osal_delay, the slave will not receive the second data packet.

The same is true when the slave device is configured in RX only mode.

0 Sunil Kumar M S over 4 years ago in reply to chun chu1

TI__Genius 12360 points

Hi Chun,

Can you add Osal_delay with minimum value based on your data transfer. As in your case slave need some time to receive data.

Osal_delay accepts timeout param in ms.

Regards,

Sunil Kumar M S

0 chun chu1 over 4 years ago in reply to Sunil Kumar M S

Intellectual 330 points

Hi Sunil,

I tried to modify the slave ISR so that it can automatically receive continuously, and increase the priority of the SPI interrupt to solve this problem.

Thank you for your support.

0 Sunil Kumar M S over 4 years ago in reply to chun chu1

TI__Genius 12360 points

Hi Chun,

Thank you for the confirmation. Can we close this thread?If any issues please reopen.

Regards,

Sunil Kumar M S

0 chun chu1 over 4 years ago in reply to Sunil Kumar M S

Intellectual 330 points

Hi Sunil,

no problem, thank you.

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TDA4VM: TDA4 - About the delay time after SPI transmission is completed