Data transfer through the SPI interface

Andrey Savinkov

Hello,

I am using OMAPL-137 DSP.

I need transfer data coming from serial ADC through the SPI interface of DSP. I am going to use DMA in order to read data from the ADC. But I'm beginner in work with .

I read SPRUFM4I and SPRUH77A, but I have no idea how to start programming. Could you hekp me and tell me steps which I have to do ?

Can I use any CSL or similar packages (without Linux) ? Or I have to configure the SPI directly through registers ?

Thank you !

over 13 years ago

0 Rahul Prabhu over 13 years ago

TI__Guru** 116170 points

Andrey,

The examples for C674x are based on DSP/BIOS drivers: PSP (platform support package). Getting started with C6747 DSP on the OMAPL137 is described here:

http://processors.wiki.ti.com/index.php/Getting_Started_Guide_for_C6747

A CSL package that was generally supported on older devices consisted of register and functional CSL. So If you are looking for register CSL kind of examples, you can find that under C:\Program Files\Texas Instruments\pspdrivers_xx_xx_xx\packages\ti\pspiom\cslr\evm6747\examples.

There is a SPI example in the PSP package which configures the peripheral in master mode but you will need SPI in Slave mode to read data from the ADC.

Regards,

Rahul

0 Andrey Savinkov over 13 years ago in reply to Rahul Prabhu

Intellectual 375 points

Thank you Rahul !

I try to read data from ADC in slave mode through SPI1. However I faced with problems. I set registers:

/* First reset the SPI chip                                               */
    spiRegs->SPIGCR0 = CSL_FMK(SPI_SPIGCR0_RESET, CSL_SPI_SPIGCR0_RESET_IN_RESET);

    /* now bring the chip out of reset state                                  */
    spiRegs->SPIGCR0 = CSL_FMK(SPI_SPIGCR0_RESET, CSL_SPI_SPIGCR0_RESET_OUT_OF_RESET);

    /* enable the CLKMOD and MASTER bits in the SPI global control reg        */
    spiRegs->SPIGCR1 |= CSL_FMK(SPI_SPIGCR1_MASTER,0x00)                   // 0x00 - Slave !
                                 | CSL_FMK(SPI_SPIGCR1_CLKMOD,0x00);                  // 0x00 - Slave !

     /* enable the pins so that they are used for the SPI interface(Multiplex) */
    spiRegs->SPIPC0 = CSL_FMK(SPI_SPIPC0_CLKFUN ,0x01)
                                         | CSL_FMK(SPI_SPIPC0_SOMIFUN ,0x01)
                                 | CSL_FMK(SPI_SPIPC0_SIMOFUN ,0x01);


    /* enable the pins so that they are used for the SPI interface(PC1) */
   spiRegs->SPIPC1 =
                                 CSL_FMK(SPI_SPIPC1_SOMIDIR ,0x01)
                                 | CSL_FMK(SPI_SPIPC1_SIMODIR ,0x00)
                                 | CSL_FMK(SPI_SPIPC1_CLKDIR ,0x00)
                                 | CSL_FMK(SPI_SPIPC1_SCS0DIR0 ,0x00) ;

    /* configure the data format in SPIFMT                                    */
    spiRegs->SPIFMT[0] = CSL_FMK(SPI_SPIFMT_CHARLEN,SPI_NUM_OF_TXBITS)
                                    | CSL_FMK(SPI_SPIFMT_PRESCALE,0x02);

    /* set the preconfigure data format as 0 which is already set above       */
    spiRegs->SPIDAT1 = CSL_FMKT(SPI_SPIDAT1_DFSEL,FORMAT0);

    spiRegs->SPIINT0 = CSL_FMKT(SPI_SPIINT0_RXINTENA,DISABLE);

    spiRegs->SPIGCR1 |= CSL_FMK(SPI_SPIGCR1_ENABLE,0x01);

Reading data:

#define SPI_NUM_OF_TXBITS 8
#define SPI_NEW_DATA_NO 0x01

CSL_SpiRegsOvly spiRegs=(CSL_SpiRegsOvly)CSL_SPI_1_REGS;

while ((CSL_FEXT(spiRegs->SPIBUF,SPI_SPIBUF_RXEMPTY)) == SPI_NEW_DATA_NO);

test = (CSL_FEXT(spiRegs->SPIBUF,SPI_SPIBUF_RXDATA));

No data is received ! I cannot find error in my code. How to set OMAPL137 in Slave mode ?

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Data transfer through the SPI interface